Hello, Codeforces!

It is the last call to register for the 2nd “Hello Muscat 2023” ICPC programming bootcamp, the continuation of the “Hello” bootcamp series, organised by Harbour.Space University, in collaboration with PhazeRo, Gutech, UK Oman Digital Club, Leagues of Code, Gutech CS Club and Codeforces!

We are inviting all of you to join us from March 8th to March 16th, 2023 in Muscat, Oman for an intense 8 days of programming! It is not only a great opportunity to train but also a chance to discover a new amazing country. March is an especially great time to visit Oman if you want to enjoy nice beach weather — don’t miss it!

As always, we can’t wait to see you there to learn, practice and compete on the international stage, smoothing your road towards the joined World Finals 2022 and 2023 in Egypt!

Our coaching line-up combines talent and experience, featuring ICPC world champions winners and finalists, as well as legendary names from the field of competitive programming: Mike Mirzayanov MikeMirzayanov, Yahor Dubovik 244mhq, Artem Plotkin Rox, Maksym Oboznyi MaksymOboznyi, Gleb Evstropov GlebsHP and Nikolay Budin budalnik.

It will be an amazing opportunity for teams from all over the world to learn from these well-known and successful coaches in the ICPC world!

The Bootcamp will be split into three divisions:

• Division A. Division A will be a mirror of the Petrozavodsk Programming Camp. Suitable for teams who already qualified for the world finals ICPC or are aiming that high.

• Division B. Designed to help teams prepare for the next season of ICPC regional competitions.

• Division C. Designed for newcomers to the world of ICPC competitive programming. For those with a handle on the basics but want to compete in future regional competitions, this division is the perfect starting point.

Tentative Schedule:

*Topic will be decided based on participants’ levels

**Schedule time is in GMT+4

Types of participation: On-Site and Online

We believe that participation in our Bootcamp should be accessible by all teams wherever they are and that is why we made onsite and online types of participation.

Full Scholarships Available: Online

We are delighted to invite all the recent medalists, eligible finalists and teams ICPC, IOI and IMO 2022 and 2023 to join our Bootcamp for FREE online. Please register using a promo code IOI_IMO_ICPC_FINALIST. Note that we will ask for proof of your full scholarship eligibility. On a case by case basis we may also consider granting full scholarship to Codeforces members with rating above 2200 (promo code — CF2200), do not hesitate to apply!

Standard Participation Fees:

Daily schedule: On-Site and Online

On-site

Online

You can ask any questions by email: [email protected]

Hello, Codeforces!

We are pleased to announce the second “Hello Muscat 2023” ICPC programming bootcamp, the continuation of the “Hello” bootcamp series, organised by Harbour.Space University, in collaboration with PhazeRo, Gutech, UK Oman Digital Club, Leagues of Code, Gutech CS Club and Codeforces!

We are inviting all of you to join us from March 8th to March 16th, 2023 in Muscat, Oman for an intense 8 days of programming! It is not only a great opportunity to train but also a chance to discover a new amazing country. There are many reasons why you must visit Oman at least once in your life, from its great people to its natural beauty and surrounding peace. March is an especially great time to visit Oman if you want to enjoy nice beach weather — don’t miss it!

As always, we can’t wait to see you there to learn, practice and compete on the international stage, smoothing your road towards the joined World Finals 2022 and 2023 in Egypt!

Our coaching line-up combines talent and experience, featuring ICPC world champions winners and finalists, as well as legendary names from the field of competitive programming: Mike Mirzayanov MikeMirzayanov, Yahor Dubovik 244mhq, Artem Plotkin Rox, Maksym Oboznyi MaksymOboznyi and Nikolay Budin budalnik.

It will be an amazing opportunity for teams from all over the world to learn from these well-known and successful coaches in the ICPC world!

The Bootcamp will be split into three divisions:

• Division A. Division A will be a mirror of the Petrozavodsk Programming Camp. Suitable for teams who already qualified for the world finals ICPC or are aiming that high. Participants of division A will be solving contests in the same conditions as a real competition to perform with more confidence in the ICPC world finals.

• Division B. Designed to help teams prepare for the next season of ICPC regional competitions. Appropriate as an introduction for teams and students just getting their foot in the door of the world of ICPC and competitive programming competitions in general. Division B will have thematic contests and lectures.

• Division C. Designed for newcomers to the world of ICPC competitive programming. For those with a handle on the basics but want to compete in future competitions and possible regionals, this division is the perfect starting point.

Types of participation: On-Site and Online

We believe that participation in our Bootcamp should be accessible by all teams wherever they are and that is why we made onsite and online types of participation.

20% Early Bird Discount is offered to universities and participants who register and pay before Jan 31st 2023.

You can ask any questions by email: [email protected]

Hey, Codeforces!

Harbour.Space University and Leagues of Code make a programming camp in Barcelona!

Leagues of Code is the official trainer of the Spanish National Olympics Team in Informatics.

Our Summer Camp is a training program that will teach participants competitive programming. It will take place in Barcelona and online on July 18-29, both participation formats are available. We are inviting students ages 10 to 24, interested in improving their skills or seeking for intensive, high level training prior to the IOI. Teachers in the camp will be 244mhq, MaksymOboznyi, pashka, and others. Participants will be divided into classes based on their level and previous experience. Classes will be held in English.

Join a coding camp that brings you the brightest stars in tech!

Get 30% discount for an on-site participation or 50% discount for online participation with promocode CFLOC2022.

Hope you all enjoyed the problemset! Editorials to problems H and I are not ready yet, we will add them as soon as possible. We apologize for weak pretests and easy problems for top participants.

By the way, solution authors did not necessarily prepare the problems. The solutions were chosen at random.

UPD. Editorials for H and I are ready! Wish you all productive upsolving and high ratings!

1553A - Digits Sum

Idea: bthero Preparation: 244mhq

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
int main() {
    //freopen("input.txt", "r", stdin);
    ios_base::sync_with_stdio(false);
    int tst;
    cin >> tst;
    while (tst--) {
        int n;
        cin >> n;
        cout << (n + 1) / 10 << '\n';
    }
}

1553B - Reverse String

Idea: Errichto Preparation: Will not be revealed for now because we care for his/their safety.

q = int(input())
for i in range(q):
	s = input()
	t = input()
	n = len(s)
	m = len(t)
	ans = False
	for i in range(n):
		for j in range(0, n - i):
			k = m - 1 - j
			if i + j < k:
				continue                                 
			l1 = i
			r = i + j
			l2 = r - k                                
			if s[l1:r+1] + s[l2:r][::-1] == t:
				ans = True	
	print('YES' if ans else 'NO')

1553C - Penalty

Idea: Errichto Preparation: BledDest

#include <bits/stdc++.h>

using namespace std;

int main() {
	int t;
	cin >> t;
	while (t--) {
		string s;
		cin >> s;
		int ans = 9;
		
		{
			int cnt0 = 0, cnt1 = 0;
			for (int i = 0; i < 10; ++i) {
				if (i % 2 == 0) cnt0 += s[i] != '0';
				else cnt1 += s[i] == '1'; 
				if (cnt0 > cnt1 + (10 - i) / 2) ans = min(ans, i);
				if (cnt1 > cnt0 + (9 - i) / 2) ans = min(ans, i);
			}
		}
		
		{
			int cnt0 = 0, cnt1 = 0;
			for (int i = 0; i < 10; ++i) {
				if (i % 2 == 0) cnt0 += s[i] == '1';
				else cnt1 += s[i] != '0'; 
				if (cnt0 > cnt1 + (10 - i) / 2) ans = min(ans, i);
				if (cnt1 > cnt0 + (9 - i) / 2) ans = min(ans, i);
			}
		}
		
		cout << ans + 1 << '\n';
	}
}

1553D - Backspace

Idea: Adel_SaadEddin, Zaher Preparation: Will not be revealed for now because we care for his/their safety.

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <ctime>
#include <cassert>
#include <complex>
#include <string>
#include <cstring>
#include <chrono>
#include <random>
#include <bitset>
using namespace std;

#ifdef LOCAL
	#define eprintf(...) fprintf(stderr, __VA_ARGS__);fflush(stderr);
#else
	#define eprintf(...) 42
#endif

using ll = long long;
using ld = long double;
using uint = unsigned int;
using ull = unsigned long long;
template<typename T>
using pair2 = pair<T, T>;
using pii = pair<int, int>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
	return (ull)rng() % B;
}

#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second

clock_t startTime;
double getCurrentTime() {
	return (double)(clock() - startTime) / CLOCKS_PER_SEC;
}

const int N = 200200;
int n, m;
char s[N], t[N];

bool solve() {
	scanf("%s %s", s, t);
	n = strlen(s);
	m = strlen(t);
	if (n < m) return false;
	int p = (n - m) & 1;
	int q = 0;
	int k = 0;
	for (int i = p; i < n; i++) {
		if (k == 1) {
			k = 0;
			continue;
		}
		if (q < m && s[i] == t[q]) {
			q++;
		} else {
			k++;
		}
	}
	return q == m;
}

int main()
{
	startTime = clock();
//	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);

	int T;
	scanf("%d", &T);
	while(T--) {
		if (solve())
			printf("YES\n");
		else
			printf("NO\n");
	}

	return 0;
}

1553E - Permutation Shift

Idea: bthero, 244mhq Preparation: BledDest

#include <bits/stdc++.h>     

using namespace std; 

int cycle_count(vector<int> q, int n)
{
 	for(int i = 0; i < n; i++)
 		q[i]--;
 	vector<int> used(n);
 	int ans = 0;
 	for(int i = 0; i < n; i++)
 	{
 		if(used[i] == 1) continue;
 		int j = i;
 		while(used[j] == 0)
 		{
 		 	used[j] = 1;
 		 	j = q[j];
 		}
 		ans++;
 	}
 	return ans;
}

bool check(int n, int m, int k, vector<int> p)
{
 	vector<int> q;
 	for(int i = k; i < n; i++)
 		q.push_back(p[i]);
 	for(int i = 0; i < k; i++)
 		q.push_back(p[i]);
 	return n - cycle_count(q, n) <= m;
}

void solve()
{
 	int n, m;
 	scanf("%d %d", &n, &m);
 	vector<int> p(n);
 	for(int i = 0; i < n; i++)
 		scanf("%d", &p[i]);
 	vector<int> cnt(n);
 	for(int i = 0; i < n; i++)
 	{
 	 	int offset = i + 1 - p[i];
 	 	if(offset < 0)
 	 		offset += n;
 	 	cnt[offset]++;
 	}
 	vector<int> ans;
 	for(int i = 0; i < n; i++)
 		if(cnt[i] + 2 * m >= n && check(n, m, i, p))
 			ans.push_back(i);
 	printf("%d", ans.size());
 	for(auto x : ans) printf(" %d", x);
 	puts("");
 			
}

int main()
{
	int t;
	scanf("%d", &t);
	for(int i = 0; i < t; i++)
	{
		solve(); 	
	}
}

1553F - Pairwise Modulo

Idea: 244mhq, Errichto Preparation: bthero

// chrono::system_clock::now().time_since_epoch().count()
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

template<int N> struct Fenw {
    ll t[N + 1];

    Fenw() {
        fill(t + 1, t + N + 1, 0ll);
    }

    void update(int p, ll x) {
        for (; p <= N; p |= (p + 1)) {
            t[p] += x;
        }
    }

    ll get(int p) {
        ll ret = 0;

        for (; p > 0; --p) {
            ret += t[p];
            p &= (p + 1);
        }

        return ret;
    }

    ll get(int l, int r) {
        return get(r) - get(l - 1);
    }
};

const int M = (int)3e5;

void solve() {
    int n;
    cin >> n;
    Fenw<M> A, B;
    ll pref = 0, ans = 0;

    for (int i = 1; i <= n; ++i) {
        int x;
        cin >> x;
        ans += x * (i - 1ll);
        ans += A.get(x);
        ans += pref;
        pref += x;
        
        for (int j = x; j <= M; j += x) {
            int l = j, r = min(M, j + x - 1);
            ans -= B.get(l, r) * j;
            A.update(l, -x);
        }

        B.update(x, 1);
        cout << ans << " \n"[i == n];
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int tt = 1;

    for (int i = 1; i <= tt; ++i) {
        solve();
    }

    return 0;
}

// chrono::system_clock::now().time_since_epoch().count()
#include <bits/stdc++.h>

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define debug(x) cerr << #x << " = " << x << endl

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

const int M = (int)3e5;

namespace A {
    ll t[M * 4];

    void update(int l, int r, ll x, int v = 1, int tl = 1, int tr = M) {
        if (l > r || tl > r || tr < l) {
            return;
        }

        if (l <= tl && tr <= r) {
            t[v] += x;
            return;
        }

        int mid = (tl + tr) >> 1;
        int c1 = (v << 1), c2 = (c1 | 1);

        update(l, r, x, c1, tl, mid);
        update(l, r, x, c2, mid + 1, tr);
    }

    ll get(int p, int v = 1, int tl = 1, int tr = M) {
        if (tl == tr) {
            return t[v];
        }

        int mid = (tl + tr) >> 1;
        int c1 = (v << 1), c2 = (c1 | 1);

        if (p <= mid) {
            return t[v] + get(p, c1, tl, mid);
        }
        else {
            return t[v] + get(p, c2, mid + 1, tr);
        }
    }
}

namespace B {
    ll t[M * 4];

    void update(int p, ll x, int v = 1, int tl = 1, int tr = M) {
        if (tl == tr) {
            t[v] += x;
            return;
        }

        int mid = (tl + tr) >> 1;
        int c1 = (v << 1), c2 = (c1 | 1);

        if (p <= mid) {
            update(p, x, c1, tl, mid);
        }
        else {
            update(p, x, c2, mid + 1, tr);
        }

        t[v] = t[c1] + t[c2];
    }

    ll get(int l, int r, int v = 1, int tl = 1, int tr = M) {
        if (l > r || tl > r || tr < l) {
            return 0ll;
        }

        if (l <= tl && tr <= r) {
            return t[v];
        }

        int mid = (tl + tr) >> 1;
        int c1 = (v << 1), c2 = (c1 | 1);

        return get(l, r, c1, tl, mid) + get(l, r, c2, mid + 1, tr);
    }
}

int n;

void solve() {
    cin >> n;
    ll pref = 0, ans = 0;

    rep (i, 1, n + 1) {
        int x;
        cin >> x;
        ans += x * (i - 1ll);
        ans += A::get(x);
        ans += pref;
        pref += x;
        
        for (int j = x; j <= M; j += x) {
            int l = j, r = min(M, j + x - 1);
            ans -= x * B::get(l, r) * (j / x);
            A::update(l, r, -x * (j / x));
        }

        B::update(x, 1);
        cout << ans << " \n"[i == n];
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int tt = 1;

    for (int i = 1; i <= tt; ++i) {
        solve();
    }

    return 0;
}

1553G - Common Divisor Graph

Idea: Adel_SaadEddin, Zaher, Errichto Preparation: Errichto

// gcd, AC, O((N+Q) * log^2), by Errichto
#include <bits/stdc++.h>
using namespace std;
#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
  enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
	*this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
// debug & operator << (debug & dd, P p) { dd << "(" << p.x << ", " << p.y << ")"; return dd; }

struct DSU {
	vector<int> parent;
	DSU(int m) {
		parent.resize(m + 1);
		for(int i = 0; i <= m; ++i) {
			parent[i] = i;
		}
	}
	int find(int a) {
		if(a == parent[a]) {
			return a;
		}
		return parent[a] = find(parent[a]);
	}
	void uni(int a, int b) {
		parent[find(a)] = find(b);
	}
};

int main() {
	// 1) read input
	int n, q;
	scanf("%d%d", &n, &q);
	vector<int> a(n);
	for(int i = 0; i < n; ++i) {
		scanf("%d", &a[i]);
	}
	int m = *max_element(a.begin(), a.end());
	// 2) prime sieve
	vector<vector<int>> prime_divisors(m + 2);
	for(int p = 2; p <= m + 1; ++p) {
		if(prime_divisors[p].empty()) {
			for(int j = p; j <= m + 1; j += p) {
				prime_divisors[j].push_back(p);
			}
		}
	}
	// 3) DSU, find initial connected components
	DSU dsu(m + 2);
	for(int x : a) {
		for(int p : prime_divisors[x]) {
			dsu.uni(x, p);
		}
	}
	// 4) DSU, find edges of cost 1
	set<pair<int,int>> edges;
	for(int x : a) {
		vector<int> nodes = prime_divisors[x+1];
		nodes.push_back(x);
		for(int& node : nodes) {
			node = dsu.find(node);
		}
		for(int i = 0; i < (int) nodes.size(); ++i) {
			for(int j = i + 1; j < (int) nodes.size(); ++j) {
				int one = nodes[i];
				int two = nodes[j];
				if(one != two) {
					if(one > two) {
						swap(one, two);
					}
					edges.insert({one, two});
				}
			}
		}
	}
	debug() << imie(edges);
	cerr << imie(edges.size()) << endl;
	// 5) answer queries
	while(q--) {
		int s, t;
		scanf("%d%d", &s, &t);
		--s;
		--t;
		s = dsu.find(a[s]);
		t = dsu.find(a[t]);
		if(s == t) {
			puts("0");
		}
		else if(edges.count({min(s, t), max(s, t)})) {
			puts("1");
		}
		else {
			puts("2");
		}
	}
}

1553H - XOR and Distance

Idea: 244mhq Preparation: BledDest, mnaeraxr, 244mhq

#include<bits/stdc++.h>

using namespace std;

const int INF = int(1e9);
const int K = 20;

struct node
{
 	int max_val, min_val, ans, len;
 	node* left;
 	node* right;

 	void recalc()
 	{
 		len = left->len + right->len;
 		max_val = max(left->max_val, right->max_val + left->len);
 		min_val = min(left->min_val, right->min_val + left->len);
 	 	ans = min(min(left->ans, right->ans), min(INF, right->min_val - left->max_val + left->len));
 	}

 	node(int x)
 	{
 	 	ans = INF;
 	 	len = 1;
 	 	if(x == 1)
 	 	 	max_val = min_val = 0;
 	 	else
 	 	{
 	 	 	max_val = -INF;
 	 	 	min_val = INF;
 	 	}
 	}

 	node(node* l, node* r)
 	{
 	 	left = l;
 	 	right = r;
 	 	recalc();
 	}

 	node() {};
};

int cnt[1 << K];
node tree[2 << K];

int n, k, m;

void build(int v, int l, int r)
{
 	if(l == r - 1)
 		tree[v] = node(cnt[l]);
 	else
 	{
 		int m = (l + r) / 2;
 		build(v * 2 + 1, l, m);
 		build(v * 2 + 2, m, r);
 		tree[v] = node(&tree[v * 2 + 1], &tree[v * 2 + 2]); 	
 	}
 	//cerr << v << " " << l << " " << r << " " << tree[v].min_val << " " << tree[v].max_val << " " << tree[v].len << " " << tree[v].ans << endl;
}

void swap_segments(node* v, int d)
{
	if(d == 0)
	{
	 	swap(v->left, v->right);
	 	v->recalc();
 	}
 	else
 	{
 	 	swap_segments(v->left, d - 1);
 	 	swap_segments(v->right, d - 1);	
 	 	v->recalc();
 	}
 	//cerr << v->min_val << " " << v->max_val << " " << v->len << " " << v->ans << endl;
}

int res[1 << K];

int cur = 0;

void rec(int x)
{
    if(x == 0)
     	res[cur] = tree[0].ans;
    else
    	rec(x - 1);
    swap_segments(&tree[0], x);
    cur ^= (1 << (k - x - 1));
    if(x == 0)
    	res[cur] = tree[0].ans;
    else
    	rec(x - 1);
}	

int main()
{            
	scanf("%d %d", &n, &k);
	for(int i = 0; i < n; i++)
	{
		int x;
	 	scanf("%d", &x);
	 	cnt[x]++;
	}
	m = 1 << k;
	build(0, 0, m);
	rec(k - 1);
	for(int i = 0; i < m; i++)
		printf("%d ", res[i]);
	puts("");
}

#include<bits/stdc++.h>

using namespace std;

const int INF = int(1e9);
const int K = 20;

struct node
{
 	int max_val, min_val, ans, len;
 	
 	node(const node& left, const node& right)
 	{
 		len = left.len + right.len;
 		max_val = max(left.max_val, right.max_val + left.len);
 		min_val = min(left.min_val, right.min_val + left.len);
 	 	ans = min(min(left.ans, right.ans), min(INF, right.min_val - left.max_val + left.len));
 	}

 	node(int x)
 	{
 	 	ans = INF;
 	 	len = 1;
 	 	if(x == 1)
 	 	 	max_val = min_val = 0;
 	 	else
 	 	{
 	 	 	max_val = -INF;
 	 	 	min_val = INF;
 	 	}
 	}

 	node() {};
};

int cnt[1 << K];
vector<node> tree[2 << K];	

void build(int v, int l, int r)
{
	tree[v].resize(r - l);
 	if(l == r - 1)
 	{
 		tree[v][0] = node(cnt[l]);	
 	}
 	else
 	{
 	 	int m = (l + r) / 2;
 	 	build(v * 2 + 1, l, m);
 	 	build(v * 2 + 2, m, r);
 	 	for(int i = 0; i < m - l; i++)
 	 	{
 	 		tree[v][i] = node(tree[v * 2 + 1][i], tree[v * 2 + 2][i]);
 	 		tree[v][i + (m - l)] = node(tree[v * 2 + 2][i], tree[v * 2 + 1][i]); 	
 	 	}
 	}
}

int main()
{            
	int n, k;
	scanf("%d %d", &n, &k);
	for(int i = 0; i < n; i++)
	{
		int x;
	 	scanf("%d", &x);
	 	cnt[x]++;
	}
	int m = 1 << k;
	build(0, 0, m);
	for(int i = 0; i < m; i++)
		printf("%d ", tree[0][i].ans);
	puts("");
}

1553I - Stairs

Idea: bthero, 244mhq, BledDest Preparation: BledDest, 244mhq

#include<bits/stdc++.h>

using namespace std;

#define forn(i, n) for(int i = 0; i < int(n); i++)
#define sz(a) ((int)((a).size()))
#define fore(i, l, r) for(int i = int(l); i < int(r); i++)

template<const int &MOD>
struct _m_int {
	int val;
 
	_m_int(int64_t v = 0) {
		if (v < 0) v = v % MOD + MOD;
		if (v >= MOD) v %= MOD;
		val = int(v);
	}
 
	_m_int(uint64_t v) {
		if (v >= MOD) v %= MOD;
		val = int(v);
	}
 
	_m_int(int v) : _m_int(int64_t(v)) {}
	_m_int(unsigned v) : _m_int(uint64_t(v)) {}
 
	static int inv_mod(int a, int m = MOD) {
		int g = m, r = a, x = 0, y = 1;
 
		while (r != 0) {
			int q = g / r;
			g %= r; swap(g, r);
			x -= q * y; swap(x, y);
		}
 
		return x < 0 ? x + m : x;
	}
 
	explicit operator int() const { return val; }
	explicit operator unsigned() const { return val; }
	explicit operator int64_t() const { return val; }
	explicit operator uint64_t() const { return val; }
	explicit operator double() const { return val; }
	explicit operator long double() const { return val; }
 
	_m_int& operator+=(const _m_int &other) {
		val -= MOD - other.val;
		if (val < 0) val += MOD;
		return *this;
	}
 
	_m_int& operator-=(const _m_int &other) {
		val -= other.val;
		if (val < 0) val += MOD;
		return *this;
	}
 
	static unsigned fast_mod(uint64_t x, unsigned m = MOD) {
#if !defined(_WIN32) || defined(_WIN64)
		return unsigned(x % m);
#endif
		// Optimized mod for Codeforces 32-bit machines.
		// x must be less than 2^32 * m for this to work, so that x / m fits in an unsigned 32-bit int.
		unsigned x_high = unsigned(x >> 32), x_low = unsigned(x);
		unsigned quot, rem;
		asm("divl %4\n"
			: "=a" (quot), "=d" (rem)
			: "d" (x_high), "a" (x_low), "r" (m));
		return rem;
	}
 
	_m_int& operator*=(const _m_int &other) {
		val = fast_mod(uint64_t(val) * other.val);
		return *this;
	}
 
	_m_int& operator/=(const _m_int &other) {
		return *this *= other.inv();
	}
 
	friend _m_int operator+(const _m_int &a, const _m_int &b) { return _m_int(a) += b; }
	friend _m_int operator-(const _m_int &a, const _m_int &b) { return _m_int(a) -= b; }
	friend _m_int operator*(const _m_int &a, const _m_int &b) { return _m_int(a) *= b; }
	friend _m_int operator/(const _m_int &a, const _m_int &b) { return _m_int(a) /= b; }
 
	_m_int& operator++() {
		val = val == MOD - 1 ? 0 : val + 1;
		return *this;
	}
 
	_m_int& operator--() {
		val = val == 0 ? MOD - 1 : val - 1;
		return *this;
	}
 
	_m_int operator++(int) { _m_int before = *this; ++*this; return before; }
	_m_int operator--(int) { _m_int before = *this; --*this; return before; }
 
	_m_int operator-() const {
		return val == 0 ? 0 : MOD - val;
	}
 
	friend bool operator==(const _m_int &a, const _m_int &b) { return a.val == b.val; }
	friend bool operator!=(const _m_int &a, const _m_int &b) { return a.val != b.val; }
	friend bool operator<(const _m_int &a, const _m_int &b) { return a.val < b.val; }
	friend bool operator>(const _m_int &a, const _m_int &b) { return a.val > b.val; }
	friend bool operator<=(const _m_int &a, const _m_int &b) { return a.val <= b.val; }
	friend bool operator>=(const _m_int &a, const _m_int &b) { return a.val >= b.val; }
 
	_m_int inv() const {
		return inv_mod(val);
	}
 
	_m_int pow(int64_t p) const {
		if (p < 0)
			return inv().pow(-p);
 
		_m_int a = *this, result = 1;
 
		while (p > 0) {
			if (p & 1)
				result *= a;
			a *= a;
			p >>= 1;
		}
 
		return result;
	}
 
	friend ostream& operator<<(ostream &os, const _m_int &m) {
		return os << m.val;
	}
};
 
extern const int MOD = 998244353;
using Mint = _m_int<MOD>;

const int LOGN = 19;
const int N = (1 << LOGN);
const int T = 2;          
Mint g = 3;

vector<Mint> w[LOGN];
vector<int> rv[LOGN];

void precalc() {
	Mint wb = Mint(g).pow((MOD - 1) / (1 << LOGN));
	forn(st, LOGN - 1) {
		w[st].assign(1 << st, 1);
		Mint bw = wb.pow(1 << (LOGN - st - 1));
		Mint cw = 1;
		forn(k, 1 << st) {
			w[st][k] = cw;
			cw *= bw;
		}
	}
	forn(st, LOGN) {
		rv[st].assign(1 << st, 0);
		if (st == 0) {
			rv[st][0] = 0;
			continue;
		}
		int h = (1 << (st - 1));
		forn(k, 1 << st)
			rv[st][k] = (rv[st - 1][k & (h - 1)] << 1) | (k >= h);
	}
}

void ntt(vector<Mint> &a, bool inv) {
	int n = sz(a);
	int ln = __builtin_ctz(n);
	forn(i, n) {
		int ni = rv[ln][i];
		if (i < ni) swap(a[i], a[ni]);
	}
	forn(st, ln) {
		int len = 1 << st;
		for (int k = 0; k < n; k += (len << 1)) {
			fore(pos, k, k + len){
				Mint l = a[pos];
				Mint r = a[pos + len] * w[st][pos - k];
				a[pos] = l + r;
				a[pos + len] = l - r;
			}
		}
	}
	if (inv) {
		Mint rn = Mint(n).inv();
		forn(i, n) a[i] *= rn;
		reverse(a.begin() + 1, a.end());
	}
}

vector<Mint> mul(vector<Mint> a, vector<Mint> b) {
	int cnt = 1 << (32 - __builtin_clz(sz(a) + sz(b) - 1));
	a.resize(cnt);
	b.resize(cnt);
	ntt(a, false);
	ntt(b, false);
	vector<Mint> c(cnt);
	forn(i, cnt) c[i] = a[i] * b[i];
	ntt(c, true);
	while(c.size() > 1 && c.back() == 0)
		c.pop_back();
	return c;
}

struct dp
{
 	vector<Mint> val[T][T];
 	bool is_unit;

 	dp() {};
 	dp(int len)
 	{
 		is_unit = len == 1;
 		for(int j = 0; j < T; j++)
 			for(int k = 0; k < T; k++)
 				val[j][k] = {0};
 		if(len == 1)
 			val[0][0][0] = 1;
 		else
 			val[1][1][0] = 2;
 	}

 	dp(const dp& a, const dp& b)
 	{
 		is_unit = false;
 		for(int l1 = 0; l1 < T; l1++)
 			for(int r1 = 0; r1 < T; r1++)
 				for(int l2 = 0; l2 < T; l2++)
 					for(int r2 = 0; r2 < T; r2++)
 					{
 					 	vector<Mint> cur = mul(a.val[l1][r1], b.val[l2][r2]);
 					 	if(val[l1][r2].size() < cur.size())
 					 		val[l1][r2].resize(cur.size());
 					 	for(int i = 0; i < cur.size(); i++)
 							val[l1][r2][i] += cur[i];
 					 	Mint merge_coeff = 2;
 					 	if(r1 == 1)
 					 		merge_coeff /= 2;
 					 	if(l2 == 1)
 					 		merge_coeff /= 2;
 					 	cur.insert(cur.begin(), 0);
 					 	for(int i = 0; i < cur.size(); i++)
 					 		cur[i] *= merge_coeff;
 					 	int L1 = l1;
 					 	int R2 = r2;
 					 	if(a.is_unit)
 					 		L1 = 1;
 					 	if(b.is_unit)
 					 		R2 = 1;
 					 	if(val[L1][R2].size() < cur.size())
 					 		val[L1][R2].resize(cur.size());
 					 	for(int i = 0; i < cur.size(); i++)
 					 	{
 					 		val[L1][R2][i] += cur[i];
 						}
 				 	}
 	}
};

ostream& operator<<(ostream& out, const dp& a)
{
 	for(int i = 0; i < T; i++)
 		for(int j = 0; j < T; j++)
 		{
 		 	out << "[" << i << "][" << j << "]";
 		 	for(auto x : a.val[i][j])
 		 		out << " " << x;
 		 	out << endl;
 		}
 	return out;
}

int a[N];
int len[N];
Mint fact[N];
int n;
int s;

dp build(int l, int r)
{
 	if(l == r - 1)
 	{
 		dp res(len[l]);   
 		//cerr << l << " " << r << endl;
 	 	//cerr << res;
 	 	return res;
 	}                     
 	else
 	{
 		int m = (l + r) / 2;
 		dp res(build(l, m), build(m, r));
 		//cerr << l << " " << r << endl;
 		//cerr << res;
 		return res;                         
 	}
}

int main()
{
	precalc();
	scanf("%d", &n);
	for(int i = 0; i < n; i++)
	 	scanf("%d", &a[i]);
	int cur = 0;
	while(cur != n)
	{
	 	if(cur + a[cur] > n)
	 	{
         	cout << 0 << endl;
         	return 0;
        }
        for(int l = cur; l < cur + a[cur]; l++)
        	if(a[l] != a[cur])
        	{
        	 	cout << 0 << endl;
        	 	return 0;
        	}
        len[s++] = a[cur];
        cur += a[cur];
	}
	
	fact[0] = 1;
	for(int i = 1; i <= s; i++)
		fact[i] = i * fact[i - 1];

	dp res = build(0, s);

	Mint ans = 0;
	for(int i = 0; i < s; i++)            
		for(int j = 0; j < T; j++)
			for(int k = 0; k < T; k++)
				if(res.val[j][k].size() > i)
					ans += fact[s - i] * res.val[j][k][i] * (i % 2 == 0 ? 1 : MOD - 1);
	cout << ans << endl;
}

Hey, Codeforces!

We have great news for you.

Harbour.Space University is excited to announce a new contest for all interested programmers who want to start their studies in Barcelona, Spain or Bangkok, Thailand, and join our ICPC team.

The contest will be hosted on the Codeforces platform Jul/22/2021 17:35 (Moscow time). We have prepared 9 problems of the joined (Div1 + Div2) level. The round will be rated and open for everyone.

UPD: Scoring distribution: 250-500-750-1250-1750-2500-3000-3750-5250

UPD2: The editorial is out!

For the next academic year (2021/22), we are recruiting a fascinating community of competitive programmers from the top prize-winners of international Olympiads to join one of our competitive programming teams at the university.

In the next few years, our goal is to win SWERC and compete at a high level in the ICPC globally. Therefore we want to invest a serious amount of our energy, resources, and talent into these activities.

That’s why we are inviting you on an exciting journey in the company of like-minded people, outstanding coaches, and our ongoing partnership with Codeforces.

We have already organized over 100 educational rounds, so we think the time has come to test our joint efforts and reward the most diligent.

Here’s what you win if you place in the contest:

,

The monthly living allowance throughout the entire duration of studies depends on the overall performance of the candidate. As a guidance, it is in the range of 500-1500 EUR (it might be applied to the contestants who win 4th-10th places).

*No application fee is required for any of the awards listed above.

We would like to say a word of appreciation to:

• Round Coordinator: BledDest
• Authors: 244mhq, bthero, Adel_SaadEddin, Zaher, Errichto, mnaeraxr.
• Testers: nooinenoojno, 998kover, Utkarsh.25dec, Um_nik, adedalic, Wind_Eagle, abunyawa, aniervs, hitonanode, Aidos, thenymphsofdelphi, ptd, ZetaZomB, rumazius, madxmad, I.AM.THE.WILL, Vladik.
• MikeMirzayanov for Polygon, Codeforces, partnership with Harbour.Space and making this round happen :)

UPD3: Congratulations to the award winners!

Note1: All the winners get an application fee waiver.
Note2: All of you eligible for Competitive Programming Scholarships (cf rating > 2000) may apply directly through our website and go through the general admissions process.

Guaranteed full scholarship + monthly living allowance + free 3-week course:
- 1 (49). Ali.Kh
- 2 (58). Yousef_Salama
- 3 (175). early-morning-dreams

A full scholarship with interview process + free 3-week course:
- 4 (184). sunyx
- 5 (200). amanbol
- 6 (203). IMRED
- 7 (219). Meijer
- 8 (226). loan
- 9 (265). kpw29
- 10 (267). Huah2

Free 3-week course:
- 11 (292). dhruvsomani
- 12 (299). adamant
- 13 (326). Kaitokid
- 14 (355). RetiredPlayer
- 15 (264). c8kbf

Good luck, and may the code be with you!

Harbour.Space University

Hello Codeforces!

We are teaming up with Polyup to offer a unique work-study apprenticeship for a Full-Stack Developer, right here in sunny Barcelona!

Based in Silicon Valley, this progressive EdTech company focuses on providing access to quality math and computational thinking programs at a global scale. Want to join this dynamic team of tech-disruptors? See the details below!

Apprenticeship Summary:

• Full tuition scholarship to study a Master’s degree in Computer Science for one year (scholarship value: €22,900)
• 3 hours of classes per day at Harbour.Space
• Internship at Polyup (remote)
• Competitive compensation
• Opportunity to join Polyup full-time after graduation

Please note preselected candidates will be requested to pay a non-refundable application fee of 125€ to study at Harbour.Space University.

Apply now at: https://www.linkedin.com/jobs/view/1998101008/

Looking forward to seeing your applications!

Hi Codeforces,

As part of its prevention of the spread of the Covid-19, the Omani government has taken the unprecedented decision to postpone all international events and to temporarily restrict the entrance to the country for people traveling from territories with coronavirus cases. We regret to inform you that, as a result, the Hello Muscat Programming Bootcamp will, unfortunately, be postponed to a later date.

Following last year’s memorable event, we were keenly looking forward to another successful bootcamp. However, as organizers, the safety and wellbeing of our participants is our first priority, so we understand that postponing the event is the best decision for everyone.

We’re working closely with our partners to set a new date, and plan to consult all parties involved, including coaches and participants to find the most suitable date for everyone.

If you have any questions, comments, or concerns, you can get in touch with us at [email protected].

We will make sure to keep you informed of any positive developments in the organization of the event.

Best,

Harbour.Space University

Hi Codeforces!

Have you ever wanted to ask MikeMirzayanov about something in particular? Maybe how he began with Codeforces, what the challenges of running such a large platform are, or maybe some tips for becoming a top competitive programmer?

Well, we have quite an exciting announcement to make — Mike is in Barcelona at the moment for his course at Harbour.Space, and next week, we’re going to shoot an interview where he answers the community’s questions!

So, if you have a question, write it in the comments. Mike will choose and answer the top questions in his interview next week.

We will post the interview as a video on our blog, so stay tuned :)

See you around!

Hello, Codeforces!

We are thrilled to announce the second instalment of our Hello Muscat ICPC Programming Bootcamp, organized by Harbour.Space University in collaboration with Codeforces, ITMO University, GUtech University, and our local partner: Phaze Ventures. The Bootcamp’s main sponsor is British Petroleum (BP), supporting Oman’s national priorities: youth development, economic diversification and job creation.

We are also excited to let you know that Codeforces has become the main collaborator of Harbour.Space for our programming bootcamp series, and will be in charge of all the educational content, from contests to problem analysis and lectures, bringing the online legacy of the platform to a unique offline experience.

Hello Muscat will take place during 19 – 25 March 2020 and will feature ICPC world champions and finalists as well as legendary names from the field of competitive programming:

Mike MikeMirzayanov Mirzayanov, Nikolai KAN Kalinin, Andrey andrewzta Stankevich, Artem VArtem Vasilyev, Mikhail darnley Dvorkin, and more coaches to be announced soon!

The bootcamp will be available to teams of different skill levels, separated by two divisions of difficulty:

• Division B: Designed to help teams prepare for the next season of ICPC regional competitions.
• Division C: Designed for newcomers to the world of ICPC competitive programming. This division is the perfect starting point for those with a handle on the basics but who want to compete in future competitions and possible regionals.

Single participants and teams must register before January 30th to receive the 15% off Early Bird Discount.
Universities and individual participants that took part in our previous bootcamps and who register for this edition will receive the 20% off Loyalty Discount.

That’s all from us. Head over to our webpage to find out more, and see you in Muscat!

Codeforces! This is a special announcement!

Last year, we had a contest for Tech Scouts, our two week International Summer Camp of Science, Technology, Design and Leadership held in July. The top performers received a full tuition waiver to attend the camp free of charge!

This year, it’s on again — same rules, same prize...round 2. Are you ready?

What it is?

Harbour.Space University, the International Tournament of Young Mathematicians (ITYM) and St. Paul's International School Barcelona have designed a special online test for high school students, to take place on May 5th at 15.00 CET Time.

We’ve prepared it to test your level in both maths and computer science, and, similarly to last year, the top performers have a chance to win two weeks in Tech Scouts: our maths and computer science summer camp for gifted youth. The camp, created for high school pupils aged 12-18, will take place from the 8th to the 19th of July in Barcelona, Spain, and is taught entirely in English.

How it works?

You can take part in the online test if all the following conditions are met:

1. Between the ages of 12 to 18,
2. Have not graduated from high school
3. Eligible to take part in IOI/IMO 2020.

The top performers of the online contest will be invited for a personal interview to demonstrate understanding of the problems solved during the contest. After the test, the most successful performers will be interviewed and awarded a full tuition waiver to attend the advanced level of the Advanced Technical Track of Tech Scouts alongside the winners of ITYM and Catalan Olympiad of Informatics.

Tech Scouts is designed to lay out the foundation of knowledge in mathematics and computer science for the next phase of higher learning. During a two-week intensive training, the students will follow a college level curriculum and discover their passions by getting to know one of Europe’s leading institutions in technology, design, and entrepreneurship.

In order to register for the contest, please fill out this form before May 3rd, 2019. All participants of the contest will get a 20% discount link to attend Tech Scouts.

If you have any questions, please don’t hesitate to ask! If not, best of luck with the contest, and we hope to see you guys soon!

Until then, you can keep up with Harbour.Space by checking out our Instagram @harbour.space :)

Happy coding! Harbour.Space University

Hello, Codeforces!

Happy Holidays from us at Harbour.Space University, and good luck on the Good Bye 2018 round This year’s Final Round has a special prize — as you might know, we’ve prepared a new installment to the “Hello! Programming Bootcamps”...this time, our destination is the pearl of the Middle East — Muscat, Oman.

So, as a special prize for this Final Codeforces Round, the top 3 participants, who are also eligible for ICPC 2019/2020 season, will be invited to form a team and join us in Oman for the 2019 “Hello Muscat!” Programming Bootcamp in 9 — 15 of March — sponsored with their participation fees, accommodation, and meals for the entire duration of the bootcamp (except flights)!

Registering to the the round you will be asked to confirm your eligibility for ICPC 2019/2020 season and your wish to get the prize.

About the Hello Muscat! Programming Bootcamp.

We are inviting all of you to join us during 9 — 15 March, 2019 in Muscat, the capital of Oman, for an intense 6 days of programming! As always, we can’t wait to see all of you learn, practice and compete on the international stage, smoothing your road towards the April World Finals in Porto.

How it works: “Hello Muscat!” Programming Bootcamp will run in parallel with the traditional Moscow pre-Finals ICPC Workshop — both Bootcamps’ contests will be identical, and contestants will be able to see their position in the General Leaderboard. Every day both camps will be competing simultaneously, 3,965 kilometers from each other!

World’s greatest coaches will come to Muscat!

MIKE MikeMirzayanov MIRZAYANOV — Founder & CEO of Codeforces, Coach of the ICPC World Champion Team 2006, Topcoder Open Finalist 2006, Google Code Jam Finalist: 2005-2006
FILIPP DPR-pavlin RUKHOVICH — ICPC World Finals 2014, KPI-Open – 2013 Winner
ARTEM VArtem VASILYEV — ICPC 2014 Bronze Medalist, ICPC 2015 World Champion, ITMO University
IVAN ifsmirnov SMIRNOV — Google Code Jam Finalist, ICPC Gold Medal, Silver medal

Visa in Oman

Citizens of almost all countries may obtain a single or multiple entry eVisa valid for 30 days online or receive visa on arrival in Oman.

For more information about the bootcamp, please refer to the “Hello Muscat!” page, here!

Again, best of luck with the contest, and we hope to see you in Oman!

Hello, Codeforces!

We are pleased to announce the 1st "Hello Muscat!" ICPC Programming Bootcamp, organised by Harbour.Space University with Moscow Workshops ICPC in collaboration with Moscow Institute of Physics and Technology, ITMO University, Saint Petersburg State University, GUTech University, and of course Codeforces! The Bootcamp's Gold Sponsor is Phaze Ventures, a venture capital firm and innovation platform based in Oman. The Bootcamp’s General Partner is Sberbank, the largest Russian bank and leading innovator.

We are inviting all of you to join us during 9 — 15 March, 2019 in Muscat, the capital of Oman, for an intense 7 days of programming! As always, we can't wait to see all of you learn, practice and compete on the international stage, smoothing your road towards the April World Finals in Porto.

How it works: "Hello Muscat!" Programming Bootcamp will run in parallel with the traditional Moscow pre-Finals ICPC Workshop — both Bootcamps' contests will be identical, and contestants will be able to see their position in the General Leaderboard. Every day, both camps will be competing simultaneously, 5,500 kilometers from each other!

Michael Endagorion Tikhomirov will be the Head of Programming Committee for both Muscat and Moscow. The Chief Judge of both camps will be Oleg snarknews Khristenko, and the General Coordinator is Alexey Maleev, the founder of Moscow Workshops ICPC.

All participants will have the opportunity to work under some of the most recognized coaches in the industry: Mike MikeMirzayanov Mirzayanov, Andrew andrewzta Stankevich, Michael Endagorion Tikhomirov, Gleb GlebsHP Evstropov, Artem VArtem Vasilyev, Ivan ifsmirnov Smirnov, Ilya izban Zban, and other world renowned Russian coaches. It will be an important opportunity for teams from all over the world to learn from these well-known and successful coaches in the ICPC world.

You can leave your contact details or register here — you'll be contacted upon registration.

GUtech Campus in Muscat, Oman

The campus is a first-of-its-kind project, and establishes Omani architecture at an international level.

The boot camp in Oman will be available to teams of different skill levels – separated by two divisions of difficulty:

• Division A. Designed to prepare students to excel and win medals in the next ICPC World Finals.
• Division B. Designed to help teams prepare for the next season of ICPC Regionals and international competitions. This is an appropriate introduction for teams and students without extensive experience in the world of ICPC and competitive programming competitions in general. The Division B curriculum features thematic lectures and contests.

The participation fee is unchanged: €1270 per person (cultural programme, accommodation and half-board meals included). Single participants and teams must register before 15 December to receive the 15% off Early Bird Discount, or the 20% off Loyalty Discount, which is awarded to teams that participated in previous Hello Programming Bootcamps or Moscow Workshops ICPC Bootcamps.

The final registration deadline is February 25, 2019.

You can ask any questions by email: [email protected]

Harbour.Space University and Moscow Workshops ICPC collective efforts have resulted in a series of successful programming Hello Bootcamps, which continue to expand across the globe. In order to experience the atmosphere of the events, we suggest you familiarise yourself with the photos and videos from the previous Hello Programming Bootcamps.

Here's a quick recap of the latest 3rd Hello Barcelona ICPC Programming Bootcamp.

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Hi Codeforces!

We want to remind everyone that the 3rd Hello Barcelona Programming Bootcamp, which is from Sept 26 — Oct 4, is right around the corner, and the teams are gathering from all over the world!

We, alongside world champions Moscow State University, gold medalists Moscow Institute of Physics Technology, University of Tokyo, and bronze medalist ITMO, would like to extend a warm welcome to some of the newest teams to join us from Nanjing University, Universidad de La Habana, Lund University, Reykjavik University, Colorado School of Mines, University of British Columbia and Vilnius Gediminas Technical University. The teams will be training side by side in preparation for the upcoming regionals, and 2019 World Finals — we’d love to see you there!

Be sure to register before August 1st so everyone has time to get visas if needed, and of course for the Early Bird Discount of 15% or the Loyalty Discount* of 20% off registration for the boot camp. See you there!

The loyalty discount is offered to universities and individual participants that took part in Hello Barcelona Bootcamps and Moscow Workshops ICPC.

Learn more about Barcelona ICPC Bootcamp

You can ask any questions by email: [email protected]

PREVIOUS BOOTCAMPS' PARTICIPANTS

Hello, Codeforces!

We are pleased to announce the 3rd Hello Barcelona Programming Bootcamp in collaboration with Moscow Workshops ICPC, organised by Harbour.Space University with content provided by Moscow Workshops ICPC, in collaboration with Moscow Institute of Physics and Technology, ITMO University, Saint Petersburg State University and Codeforces!

The boot camp will be held from 26 September to 4 October, 2018 in Barcelona, and hosted at the beautiful and technologically mind-bending Media-TIC building — the Smart Building of Tomorrow.

The world's greatest coaches training the participants of Moscow Workshops ICPC events will be attending the programming bootcamp: Mike MikeMirzayanov Mirzayanov, Andrey andrewzta Stankevich, Michael Endagorion Tikhomirov, Gleb GlebsHP Evstropov, Artem VArtem Vasilyev, Ivan ifsmirnov Smirnov and other world renowned Russian coaches. The Chief Judge of the camp is Oleg snarknews Khristenko. It will be an important opportunity for teams from all over the world to learn from these well-known and successful coaches in the ICPC world.

“The participants are facing the problems from real contests selected by our coaches. In competitive programming it’s very important to have real solving experience: one thing is to be able to solve problems staying in comfortable environment of one’s university but championships are completely different. The only way to get ready for the extreme conditions of ICPC is to visit our programming boot-camps”, says Alexey Maleev, the founder of Moscow Workshops ICPC.

So how do you get the most out of the camp? "I think there is no universal solution for "get the most out of a camp" – everyone should find their own path, but the general guideline will be: communicate with other participants as much as you can, make sure you do upsolving (at least some), keep track of how much you sleep," says Gleb GlebsHP Evstropov, coach.

A look back on our recent boot camp:

“Having visited all the Hello Programming Bootcamps, I left the events feeling inspired from the overall atmosphere. I am sure that all teams received an immense amount of knowledge and skill. As one of the coaches, all of the flattering reviews about the camp from the participants were pleasant for me to hear. I am very glad that these camps are becoming regular. Harbour.Space University and Moscow Workshops ICPC have done a job worthy of admiration!” says Mike MikeMirzayanov Mirzayanov.

The Bootcamp will be split into three divisions:

• Division A. Designed to prepare students to excel and win medals in the next ICPC World Finals.
• Division B. Designed to help teams prepare for the next season of ICPC Regionals and international competitions. This is an appropriate introduction for teams and students new to the world of ICPC and competitive programming competitions in general. The Division B curriculum features thematic lectures and contests.

The participation fee is unchanged: €1270 per person (cultural programme, accommodation and half-board meals included). Single participants and teams must register before July 1st, 2018 to receive the 15% off Early Bird Discount, or the 20% off Loyalty Discount, which is awarded to teams that participated in previous Hello Programming Bootcamps or Moscow Workshops ICPC boot camps.

Learn more about Barcelona ICPC Bootcamp

You can ask any questions by email: [email protected]

In order to experience the atmosphere of the event, we suggest you familiarise yourself with the photos and videos from the previous Hello Programming Bootcamps in collaboration with Moscow Workshops ICPC.

Learn more about Harbour.Space University

Please reach out to us if you have any questions about the university or our programmes: [email protected]

Harbour.Space University, the International Tournament of Young Mathematicians (ITYM) and Moscow Institute of Physics and Technology (MIPT) are proud to announce a special high schooler's online test, May 26th at 15.00 CET Time. The test will gauge your level in both maths and computer science and give a chance to win two weeks in a math and computer science summer camp for gifted youth Tech Scouts, taught in English for ages 12-18, held 16-29 of July in Barcelona, Spain.

You can take part in the online test if all the following conditions are met:

1. Between the ages of 12 to 18,
2. Have not graduated high school,
3. Eligible to take part in IOI/IMO 2019.

The top performers of the online contest will be invited for a personal interview to demonstrate understanding of the problems solved during the contest. After the test, the 100 most successful performers will be interviewed, and the top will be awarded a full tuition waiver to attend the advanced level of the Technical Track of Tech Scouts.

Tech Scouts is designed to lay out the foundation of knowledge in mathematics and computer science for the next phase of higher learning. During a two-week intensive training, the students will follow a college level curriculum and discover their passions by getting to know one of Europe’s leading institutions in design, entrepreneurship and technology.

In order to register for the contest, please fill out this type form before 11.59pm May 24. All participants of the contest will get a 25% discount promo code to attend Tech Scouts.

Register

UPD For those of you who cannot meet the required conditions, but would still like to participate, please fill out this form

UPD2 As many of you have informed us of the date coinciding with Google Code Jam round 2, we are moving the date by one week. The new date is May 26. Thank you, everyone!

Hello, Codeforces!

The First International Data Analysis Olympiad (IDAO) Began Online This January — Finals To Be Held This April in Moscow, Russia.

This is the best time to join the competition. It will be running until February 11th and the problems will be in English — if you want to take part and win a prize, register now.

Higher School of Economics, Yandex and Sberbank along with Harbour.Space University are proud to announce an olympiad created by and for data analysts.

The event aims to bridge the gap between the all-increasing complexity of Machine Learning models and performance bottlenecks of the industry. The participants will strive not only to maximize the quality of their predictions, but also to devise resource-efficient algorithms.

This will be a team machine learning competition, divided into two stages:

• The first stage will be online, open to all participants.
• The second stage will be the offline on-site finals, in which the top 30 performing teams from the online round will compete at the Yandex office in Moscow.

We would like to thank the IDAO team for their amazing work in problemsetting — Dmitry Vetrov, Andrey Chertok, GlebsHP, Alexander Guschin, Michael, Konstantin Mertsalov, Evgeny Sokolov, Vadim Strijov, Nick Tiden, Dmitry Ulyanov, Andrey Ustyuzhanin.

More information and register

STAGE 1. ONLINE

There will be two separate tracks during the online stage. From the machine learning perspective, the tracks will be similar, yet the restrictions put on the solutions are different for each track.

We hope that the two tracks will make the olympiad fascinating for both machine learning competition experts and competitive programming masters, Kaggle winners and ACM champions, as well as everyone eager to solve real world problems with Data. Moreover, we encourage people with different backgrounds, ML and ACM, to team up and push Data Analysis to new frontiers.

The first track will be a traditional data science competition. Having a labeled training data set, participants will be asked to make a prediction for the test data and submit their predictions to the leaderboard. In this track, participants can produce arbitrarily complex models. If you like to use 4-level stacking or deep neural networks, this is the right track for you – you will only need to submit test predictions. However, those who qualify for the finals will be asked to submit the full code of the solution for validation by the judges.

In real world problems, efficiency is as important as quality. Complex and resource-intensive solutions will not fit the strict time and space restrictions often imposed by an application. That is why in the second competition track, your task will be to solve the same problem as was in track one, but with tight restrictions on the time and on the memory used during both learning and inference. You will need to upload the end-to-end code for your solution: both learning and inference. The evaluation server will run training and testing for your model and report the result. Both learning and evaluation must fit into time and memory constraints. If you like the most efficient solutions, this is the right track for you.

PRIZES

Winners of the first stage will be invited to Moscow to take part in the on-site competition. Accommodation, and half-board meals are covered by the organising committee.

All participants have the chance to showcase their skills to the data science community on an international scale — the results will be internships, networking with some of the most passionate and like minded individuals, and job opportunities.

For winners, valuable prizes will be awarded, with both Higher School of Economics and Harbour.Space University offering special awards. Students from outside of Russia will have an opportunity to join a Master's degree programme at HSE, within the Faculty of Computer Science, free of charge. From Harbour.Space University, a 29,000 EUR scholarship will be offered, which also covers living costs in Barcelona, for graduate and undergraduate degrees.

Special prizes might be awarded at the discretion of the jury.

The winners will be determined by the leaderboard ranking based on private test set.

More information and register

Hello, Codeforces!

We are pleased to announce the 1st Hello India x Russia Programming Bootcamp, with Amrita School of Engineering, Moscow Institute of Physics and Technology in collaboration with Moscow Workshops ACM ICPC, and of course Codeforces!

The boot camps will be held from March 22nd to the 30th in both India and Russia.

We would like to bring your attention to the new Bootcamp Features: Hello India x Russia Programming Bootcamp and Moscow Workshops ACM-ICPC will be running both boot camps side by side, every day each camp will be competing in parallel, 7,500 kilometers from each other.

In India and Russia, the Coordinators of the Programming Committee will be both Gleb GlebsHP Evstropov and Michael Endagorion Tikhomirov, respectively.

A look back on our recent boot camp: