hoping for a good contest :)

As a tester, good luck anyone who participates will have a positive delta!

-QuangBui(YT/CP)

Anxious for the contest to arrive

PS: I take this opportunity to leave a link to a blog with a collection of segment tree problems that I hope will be helpful to someone. https://codeforces.net/blog/entry/22616

Thanks to AminAnvari

why cf is organising contest at unusual time these day? By the way hoping for big delta +ve

traktor. Me when I read A

As a tester, GOOD LUCK!

does one subtask means that one problem will be divided to easy and hard versions?

i wish i could creat a contest like this one day :3

Unusual Time

I hope you surprise us with A1 and A2

I hope to become MASTER again through this contest.

Good luck!

I want green

Good time for Chinese participants!

I wonder why recent contests take place earlier.

I don't know whether it is appropriate to post this comment under this blog.

If I registered for round #751(Div-1) and I lost candidate master after today's contest, will I be able to participate in tomorrow's Div-1?.

ppl say the unusual time of this round is because its mirroring an olympiad, but we all know the real reason is that it doesn't clash with the T20 World Cup: India vs Pakistan. Thanks Codeforces, appreciate it.

At least the first question can be easy for newbies!!!

is there gonna be score distribution?

Yay! Perfect Timing for me. Today is IND vs. PAK World T20 from 7:30 pm (UTC+5.5).

Is it rated?

Todays Contest is Awesome..... I am only able to solve one question but B and C questions solution i know but there time complexity is way too much........ Today gonna learn something new...... Very nice contest Again!!!

• Problem 1: Pretest passed in 7 mins.
• Problem 2: Pretest passed in 3 mins.
• Problem 3: Pretest passed in 12 mins.
• Problem 4: WA on pretest 2 :(

Guys does Codeforces really use Adobe Flash Player? I feel like it is a prank, I can't do hacks.

WTF is happening with me I am solving A in more than 1 hr and B,C in 30 mins is it just me or nowadays problem A is becoming trickier. I suck

Thanks for such a good contest!

WHY THE CONSTRAIN sum <= 1e9 is in D there are solutions that cut because of this what the hell is point? you could make it 2e9

How to solve E? I tried a O(n^1.5) dp approach but didn't work.

please tell me if i have submitted two pretest passed solutions for the same problem, which one will be judged for main tests??? please some one tell meee pleaseeeee

Are pretests for F1 really weak?

Someone solved the problem F2 with a Gaussian basis?

Can someone give a hint for A? I was trying it case by case but I felt like there were way too many cases with my method. In the end, I was really short on time and couldn't even enumerate all the cases.

D was nothing but x(+y) + y(-x) = 0 and x(-y) + y(x+z) + z(-y) = 0. One can easily use 1st relation to solve for even arrays but tricky part comes for odd arrays where u need to find x and z such that there sum is not 0.

How to solve A quickly?

Great problems!

I don't understand the answer for A from editorial:

cout << (a + c) % 2 << '\n';

If a=0, b=1, c=0, shouldn't the answer be 2 minutes? (not zero as the editorial suggest)

The question for the experts is, is there really not a single test in A that would reject a solution with an overflow of the int variable? https://codeforces.net/contest/1582/submission/132905404

I spent half an hour looking for a hack, for this solution, for me it became a kind of challenge...

Did anyone else solve F2 with bitset in $$$O(\dfrac{a_i^3+na_i}{w})$$$? I think that I will FST(

I needed more 5 minutes to fix my bug for D if I just didn't be like a moron in A and waste 20 min on it pfff I hope my solution is WA after fixing that bug that would actually make me feel less worst lol

Edit: Accepted but wasn't gonna make it in time without my stupidity in A anyway that actually feels even more less worst my idea is correct and I wasn't gonna make on time better than the solution is completely wrong or i just needed more 5 min to get Accepted

Problem — B

#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
using namespace std;

#define fi              first
#define se              second
#define ll             long long
#define pb              push_back
#define mp              make_pair
#define mt              make_tuple
#define pii             pair<int,int>
#define vi              vector<int>
#define mii             map<int,int>
#define all(v)          v.begin(),v.end()
#define ubound(v,val)   std::upper_bound(all(v), val)
#define pqb             priority_queue<int>
#define mnheap          priority_queue<int,vi,greater<int> > //mnheap  use less<int> for mxheap // push(),top(),pop() //
#define setbits(x)      __builtin_popcountll(x)
#define mod             1000000007
#define inf             1e18
#define FastIO             ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

int main()
{
	FastIO;
	// #ifndef ONLINE_JUDGE
	// freopen("inputf.in", "r", stdin);
	// freopen("outputf.out", "w", stdout);
	// #endif
	int t;
	cin>>t;
	while(t--)
	{
		int n;
		cin>>n;
		vector<int> arr(n);
		ll zc =0;
		ll oc=0;
		for(int i=0;i<n;i++){
			cin>>arr[i];
			// sum+=arr[i];
			if(arr[i]==0)
				zc++;
			if(arr[i]==1)
				oc++;
		}
		ll ans = (1L<<zc)*1LL;
		cout<<oc*ans<<'\n';

	}
	return 0;
}

#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
using namespace std;

#define fi              first
#define se              second
#define ll             long long
#define pb              push_back
#define mp              make_pair
#define mt              make_tuple
#define pii             pair<int,int>
#define vi              vector<int>
#define mii             map<int,int>
#define all(v)          v.begin(),v.end()
#define ubound(v,val)   std::upper_bound(all(v), val)
#define pqb             priority_queue<int>
#define mnheap          priority_queue<int,vi,greater<int> > //mnheap  use less<int> for mxheap // push(),top(),pop() //
#define setbits(x)      __builtin_popcountll(x)
#define mod             1000000007
#define inf             1e18
#define FastIO             ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

	ll power(ll a, ll b)	//a is base, b is exponent
	{
		if(b==0)
			return 1;
		if(b==1)
			return a;
		if(b%2 == 1)
			return (power(a,b-1)*a)%mod;
		ll q = power(a,b/2);
		return (q*q)%mod;
	}
int main()
{
	FastIO;
	// #ifndef ONLINE_JUDGE
	// freopen("inputf.in", "r", stdin);
	// freopen("outputf.out", "w", stdout);
	// #endif
	int t;
	cin>>t;
	while(t--)
	{
		int n;
		cin>>n;
		vector<int> arr(n);
		ll zc =0;
		ll oc=0;
		for(int i=0;i<n;i++){
			cin>>arr[i];
			// sum+=arr[i];
			if(arr[i]==0)
				zc++;
			if(arr[i]==1)
				oc++;
		}
		ll ans = power(2,zc)*1LL;
		cout<<oc*ans<<'\n';

	}
	return 0;
}

#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
using namespace std;

#define fi              first
#define se              second
#define ll             long long
#define pb              push_back
#define mp              make_pair
#define mt              make_tuple
#define pii             pair<int,int>
#define vi              vector<int>
#define mii             map<int,int>
#define all(v)          v.begin(),v.end()
#define ubound(v,val)   std::upper_bound(all(v), val)
#define pqb             priority_queue<int>
#define mnheap          priority_queue<int,vi,greater<int> > //mnheap  use less<int> for mxheap // push(),top(),pop() //
#define setbits(x)      __builtin_popcountll(x)
#define mod             1000000007
#define inf             1e18
#define FastIO             ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)

	ll power(ll a, ll b)	//a is base, b is exponent
	{
		if(b==0)
			return 1;
		if(b==1)
			return a;
		if(b%2 == 1)
			return (power(a,b-1)*a)%mod;
		ll q = power(a,b/2);
		return (q*q)%mod;
	}
int main()
{
	FastIO;
	// #ifndef ONLINE_JUDGE
	// freopen("inputf.in", "r", stdin);
	// freopen("outputf.out", "w", stdout);
	// #endif
	int t;
	cin>>t;
	while(t--)
	{
		int n;
		cin>>n;
		vector<int> arr(n);
		ll zc =0;
		ll oc=0;
		for(int i=0;i<n;i++){
			cin>>arr[i];
			// sum+=arr[i];
			if(arr[i]==0)
				zc++;
			if(arr[i]==1)
				oc++;
		}
		ll ans = pow(2,zc)*1LL;
		cout<<oc*ans<<'\n';

	}
	return 0;
}

Is'nt left shift and logarithimic power method better than pow??
anyone can explain why?? thanks in advance.

Nice problems! If problem A explanation was correct this contest was one of the great contest in cf

Problem D has shaved years off my lifespan.

FSTforces

2 minutes silence for those who got FST on F1.

I don't understand one thing

Why does xor of empty subsequence equal to zero?

Another interesting thing is that there was no such pretest in the tests.

To get F1 accepted it was more important to keep in mind that xor 0 is always possible than the fact that increasing subsequence is different from non-decreasing.

.

After the round 750, I received the message:

" Your solution 132867227 for the problem 1582C significantly coincides with solutions vpike/132864849, RefreshedCoder/132867227 "

The two solutions can be found here:

132867227 132864849

It's a simple greedy approach and I wrote every character in my IDE. It's a wrong judgement and may I ask the admin of Codeforces to examine the two submissions manually?

I personally don't know vpike and it's just a coincidence that our solutions are similar in this simple problem. I solved in total 6 problems in the round and there's no motivation for me to cheat in problem C.

Please, could anybody help me to get my rating back?

UPD: Ping MikeMirzayanov here

Can somebody hack my D? I think my submission is wrong, because I dont check this condition the sum of their absolute values cannot exceed 10^9. 132943758 upd: it is correct

Is F2 solvable with java?

Thanks for fast Editorial!

Can anyone tell me why me solution https://codeforces.net/contest/1582/submission/149071151 gives TLE on F2 If I use while loop which I have commented instead of for loop it gives AC.