Tutorial
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Solution 1
#include <bits/stdc++.h>
using namespace std;
void solve() {
int n;
scanf("%d", &n);
vector <int> in(n);
vector <int> is(N);
for(auto &p: in)
scanf("%d", &p);
for(int i = 0; i < n; ++i)
for(int j = i + 1; j < n; ++j)
is[in[j] - in[i]] = true;
int ans = 0;
for(auto &v: is)
ans += v;
printf("%d\n", ans);
}
int main() {
int cases;
scanf("%d", &cases);
while(cases--)
solve();
return 0;
}
Solution 2
#include <bits/stdc++.h>
using namespace std;
void solve() {
int n;
scanf("%d", &n);
vector <int> in(n);
for(auto &p: in)
scanf("%d", &p);
set <int> S;
for(int i = 0; i < n; ++i)
for(int j = i + 1; j < n; ++j)
S.insert(in[j] - in[i]);
printf("%d\n", (int)S.size());
}
int main() {
int cases;
scanf("%d", &cases);
while(cases--)
solve();
return 0;
}
1466B - Улучшения в последнюю минуту
Tutorial
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Solution 1
#include <bits/stdc++.h>
using namespace std;
void solve() {
int n;
scanf("%d", &n);
int ans = 0;
int prv = 0, ok = 0;
for(int i = 1; i <= n; ++i) {
int a;
scanf("%d", &a);
ans += (a != prv);
ok |= (a == prv);
if(prv + 1 < a)
ans += ok, ok = 0;
prv = a;
}
ans += ok;
printf("%d\n", ans);
}
int main() {
int cases;
scanf("%d", &cases);
while(cases--)
solve();
return 0;
}
Solution 2
#include <bits/stdc++.h>
using namespace std;
void solve() {
int n;
scanf("%d", &n);
set <int> S;
for(int i = 1; i <= n; ++i) {
int v;
scanf("%d", &v);
if(S.count(v))
v++;
S.insert(v);
}
printf("%d\n", (int)S.size());
}
int main() {
int cases;
scanf("%d", &cases);
while(cases--)
solve();
return 0;
}
Tutorial
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Solution
#include <bits/stdc++.h>
using namespace std;
const int N = 100'007;
int n;
char in[N];
bool used[N];
void solve(){
scanf("%s", in + 1);
n = strlen(in + 1);
for(int i = 1; i <= n; ++i)
used[i] = false;
int ans = 0;
for(int i = 2; i <= n; ++i){
bool use_need = false;
if(in[i] == in[i - 1] && !used[i - 1])
use_need = true;
if(i > 2 && in[i] == in[i - 2] && !used[i - 2])
use_need = true;
used[i] = use_need;
ans += used[i];
}
printf("%d\n", ans);
}
int main(){
int cases;
scanf("%d", &cases);
while(cases--)
solve();
return 0;
}
1466D - Тринадцатый подвиг Геракла
Tutorial
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Solution
#include <bits/stdc++.h>
using namespace std;
typedef long long int LL;
const int N = 100'007;
int n;
int w[N];
int deg[N];
void solve() {
scanf("%d", &n);
for(int i = 1; i <= n; ++i) {
scanf("%d", &w[i]);
deg[i] = 0;
}
for(int i = 1; i < n; ++i) {
int u, v;
scanf("%d %d", &u, &v);
deg[u]++; deg[v]++;
}
LL ans = 0;
vector <int> to_sort;
for(int i = 1; i <= n; ++i) {
for(int j = 1; j < deg[i]; ++j)
to_sort.push_back(w[i]);
ans += w[i];
}
sort(to_sort.begin(), to_sort.end());
reverse(to_sort.begin(), to_sort.end());
printf("%lld ", ans);
for(auto &v: to_sort) {
ans += v;
printf("%lld ", ans);
}
printf("%lld\n", ans);
}
int main() {
int cases;
scanf("%d", &cases);
while(cases--)
solve();
return 0;
}
Tutorial
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Solution
#include <bits/stdc++.h>
using namespace std;
typedef long long int LL;
const int N = 500'007;
const int P = 60;
const int MX = 1'000'000'007;
int n;
LL in[N];
int cnt[P];
void solve(){
scanf("%d", &n);
for(int i = 0; i < P; ++i)
cnt[i] = 0;
for(int i = 1; i <= n; ++i){
scanf("%lld", &in[i]);
for(int j = 0; j < P; ++j)
cnt[j] += in[i] >> j & 1;
}
int ans = 0;
for(int i = 1; i <= n; ++i){
LL exp_or = 0, exp_and = 0;
for(int j = 0; j < P; ++j){
if(in[i] >> j & 1){
exp_or += (1LL << j) % MX * n;
exp_and += (1LL << j) % MX * cnt[j];
}
else
exp_or += (1LL << j) % MX * cnt[j];
}
exp_and %= MX, exp_or %= MX;
ans = (ans + 1LL * exp_or * exp_and) % MX;
}
printf("%d\n", ans);
}
int main(){
int cases;
scanf("%d", &cases);
while(cases--)
solve();
return 0;
}
Tutorial
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Solution
#include <bits/stdc++.h>
using namespace std;
typedef long long int LL;
const int N = 5e5 + 7;
const int MX = 1e9 + 7;
int n, m;
int rep[N];
int Find(int a) {
if(rep[a] == a)
return a;
return rep[a] = Find(rep[a]);
}
bool Union(int a, int b) {
a = Find(a);
b = Find(b);
rep[a] = b;
return a != b;
}
int main() {
scanf("%d %d", &n, &m);
for(int i = 1; i <= m + 1; ++i)
rep[i] = i;
vector <int> ans;
for(int i = 1; i <= n; ++i) {
int k;
scanf("%d", &k);
int fa, fb = m + 1;
scanf("%d", &fa);
if(k > 1)
scanf("%d", &fb);
if(Union(fa, fb))
ans.push_back(i);
}
int res = 1;
for(int i = 0; i < (int)ans.size(); ++i)
res = (res + res) % MX;
printf("%d %d\n", res, (int)ans.size());
for(auto v: ans)
printf("%d ", v);
puts("");
return 0;
}
Tutorial
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Solution
#include <bits/stdc++.h>
using namespace std;
const int MAXLEN = 1'000'007;
const int MOD = 1'000'000'007;
int n, q;
string s, t;
vector <string> songs;
vector <int> pw;
vector <int> sum[26];
void read(string &p) {
static char input[MAXLEN];
scanf("%s", input);
p = input;
}
void prepare_songs() {
songs = {s};
for(auto c: t) {
if(songs.back().size() >= MAXLEN)
break;
auto p = songs.back();
auto nxt = p + string(1, c) + p;
songs.push_back(nxt);
}
}
void prepare_sum() {
for(int i = 0; i < 26; ++i) {
char c = 'a' + i;
sum[i].resize(n + 1, 0);
for(int j = 0; j < n; ++j)
sum[i][j + 1] = (sum[i][j] * 2 + (t[j] == c)) % MOD;
}
pw.resize(n + 1, 0);
pw[0] = 1;
for(int i = 1; i <= n; ++i)
pw[i] = 2LL * pw[i - 1] % MOD;
}
void init() {
scanf("%d %d", &n, &q);
read(s), read(t);
prepare_songs();
prepare_sum();
}
vector <int> kmp(string &in) {
int m = in.size(), cpref = 0;
vector <int> dp(m, 0);
for(int i = 1; i < (int)in.size(); ++i) {
while(cpref > 0 && in[cpref] != in[i])
cpref = dp[cpref - 1];
if(in[cpref] == in[i])
++cpref;
dp[i] = cpref;
}
return dp;
}
/* Get all borders based on dp from kmp */
vector <bool> get(vector <int> &dp, int m) {
vector <bool> ret(m + 1, false);
int cur = dp.back();
while(cur) {
ret[cur] = true;
cur = dp[cur - 1];
}
ret[cur] = true;
return ret;
}
int answer(int k, string &w) {
int id = 0;
while(songs[id].size() < w.size())
++id;
if(id > k)
return 0;
int m = w.size();
string s_pref = w + '#' + songs[id];
string s_suf = songs[id] + '#' + w;
auto dp_pref = kmp(s_pref);
auto dp_suf = kmp(s_suf);
auto pref = get(dp_pref, m);
auto suf = get(dp_suf, m);
/* Compute all internal occurences */
int ret = 0;
for(auto &v: dp_pref)
ret += (v == m);
ret = 1LL * ret * pw[k - id] % MOD;
/* Compute the remaining occurences */
for(int i = 0; i < m; ++i) {
if(!pref[i] || !suf[m - i - 1])
continue;
int c = w[i] - 'a';
ret = (ret + sum[c][k] - 1LL * sum[c][id] * pw[k - id]) % MOD;
}
ret = (ret + MOD) % MOD;
return ret;
}
void solve() {
while(q--) {
int k;
string w;
scanf("%d", &k);
read(w);
printf("%d\n", answer(k, w));
}
}
int main() {
init();
solve();
return 0;
}
1466H - Поиск удовлетворяющих решений
Tutorial
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Solution
#include <bits/stdc++.h>
using namespace std;
typedef long long int LL;
#define st first
#define nd second
#define PII pair <int, int>
const int N = 60;
const int MX = 1e9 + 7;
struct state {
int sum_picked = 0;
int last_picked = 0, cur_picked = 0;
int iterator = 0;
vector <PII> lengths;
state(vector <PII> _lengths) {
lengths = _lengths;
}
/* operators for map comparisons */
bool operator<(const state &s) const {
if(lengths != s.lengths) return lengths < s.lengths;
if(last_picked != s.last_picked) return last_picked < s.last_picked;
if(cur_picked != s.cur_picked) return cur_picked < s.cur_picked;
return iterator < s.iterator;
}
bool operator==(const state &s) const {
if(last_picked != s.last_picked) return false;
if(cur_picked != s.cur_picked) return false;
if(iterator != s.iterator) return false;
if(lengths != s.lengths) return false;
return true;
}
};
int n;
vector <PII> cycles;
map <state, int> dp;
int sil[N], rv[N];
int pre[N][N][N];
int fast(int a, int b) {
int ret = 1;
while(b) {
if(b & 1)
ret = 1LL * ret * a % MX;
b >>= 1;
a = 1LL * a * a % MX;
}
return ret;
}
int newt(int a, int b) {
if(b < 0 || a < b)
return 0;
return 1LL * sil[a] * rv[b] % MX * rv[a - b] % MX;
}
PII get_ways(int a, int b) {
if(a == 0 && b == 0)
return {sil[n - 1], 0};
int ret = 0, ret2 = 0;
int c = n - a - 1;
for(int t = 1; t + c <= n; ++t) {
ret = (ret + 1LL * newt(n - t, c) * sil[c] % MX * newt(n - c - 1, b) % MX * sil[b] % MX * sil[a - b]) % MX;
ret2 = (ret2 + 1LL * newt(n - t, c) * sil[c] % MX * newt(n - t - c, b) % MX * sil[b] % MX * sil[a - b]) % MX;
}
return {ret, ret2};
}
void precalc() {
sil[0] = 1;
for(int i = 1; i <= n; ++i)
sil[i] = 1LL * sil[i - 1] * i % MX;
rv[n] = fast(sil[n], MX - 2);
for(int i = n; i >= 1; --i)
rv[i - 1] = 1LL * rv[i] * i % MX;
for(int i = 0; i < n; ++i)
for(int j = 0; j <= i; ++j) {
if(i && j == 0)
continue;
auto [val, val2] = get_ways(i, j);
pre[i][j][0] = 1;
int res = 1, res2 = 1;
for(int k = 1; k <= n; ++k) {
res = 1LL * res * val % MX;
res2 = 1LL * res2 * val2 % MX;
pre[i][j][k] = (res + MX - res2) % MX;
}
}
}
void read() {
scanf("%d", &n);
precalc();
vector <int> input(n);
for(auto &v: input) {
scanf("%d", &v);
v--;
}
vector <bool> vis(n);
vector <int> cycle_lengths;
for(int i = 0; i < n; ++i) {
if(vis[i])
continue;
int cur = i;
int cycle_length = 0;
while(!vis[cur]) {
++cycle_length;
vis[cur] = true;
cur = input[cur];
}
cycle_lengths.push_back(cycle_length);
}
sort(cycle_lengths.begin(), cycle_lengths.end());
for(auto v: cycle_lengths) {
if(cycles.size() && cycles.back().st == v)
cycles.back().nd++;
else
cycles.push_back({v, 1});
}
}
int solve(state &cur) {
if(cur.sum_picked == n)
return 1;
if(dp.count(cur))
return dp[cur];
if(cur.iterator == (int)cur.lengths.size()) {
if(cur.cur_picked == 0)
return dp[cur] = 0;
state nxt = cur;
nxt.sum_picked += nxt.cur_picked;
nxt.last_picked = nxt.cur_picked;
nxt.cur_picked = 0;
nxt.iterator = 0;
return dp[cur] = solve(nxt);
}
state nxt = cur;
nxt.iterator++;
int ret = 0, tmp = 1;
auto [length, count] = cur.lengths[cur.iterator];
for(int i = 0; i <= count; ++i) {
nxt.cur_picked = cur.cur_picked + i * length;
nxt.lengths[cur.iterator].nd = count - i;
ret = (ret + 1LL * solve(nxt) * tmp % MX * newt(count, i)) % MX;
tmp = 1LL * tmp * pre[cur.sum_picked][cur.last_picked][length] % MX;
}
return dp[cur] = ret;
}
int main() {
read();
state start = state(cycles);
int ans = solve(start);
printf("%d\n", ans);
return 0;
}
Tutorial
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Solution
#include <bits/stdc++.h>
using namespace std;
#define st first
#define nd second
int n, b;
void write(int i, string y){
printf("%d ", i);
for(auto p: y)
printf("%c", p);
puts("");
fflush(stdout);
}
bool ask(int i, string y){
write(i, y);
string ans;
cin >> ans;
return ans == "yes";
}
void solve(vector <int> cur, string pref){
if(pref.size() == b){
write(0, pref);
return;
}
stack <pair <int, string> > S;
S.push({0, pref});
for(auto v: cur){
while(S.size() > 1){
auto prv = S.top().nd;
while(prv.size() < b)
prv.push_back('1');
if(!ask(v, prv))
break;
S.pop();
}
if(S.top().nd.size() == b)
continue;
auto prv = S.top().nd;
prv.push_back('0');
while(prv.size() < b)
prv.push_back('1');
if(ask(v, prv)){
prv = S.top().nd + "1";
S.push({v, prv});
}
else{
prv = S.top().nd + "0";
S.push({v, prv});
}
}
vector <int> nxt;
string ans = S.top().nd;
while(S.size() > 1){
auto p = S.top();
S.pop();
string tmp = ans;
while(tmp.size() < b)
tmp.push_back('1');
if(ask(p.st, tmp)){
nxt.clear();
ans = p.nd;
}
nxt.push_back(p.st);
}
solve(nxt, ans);
}
int main(){
scanf("%d %d", &n, &b);
vector <int> all_ids;
for(int i = 0; i < n; ++i)
all_ids.push_back(i + 1);
solve(all_ids, "");
return 0;
}