Hoping no problems will be there containing Game Theory. IMHO, CC should give Game Theory some rest.

BERNARB.01 orz

Another week another contest not rated for 7* coders :sob;

Amr Harb is the best.

Whenever you have subtasks you must have separate samples where sample 1 fits the constraints of subtask 1, sample 2 fits the constraints of subtask 2, etc.

SpeedChef

Was anyone able to solve Sum of Xors(SMXR)?

I thought it would be just (N*M*3)/2 but that's wrong, can someone please explain?

[WRONG]

Not a fan of "knowledge-based" problems like "Number Hunt". Its pretty much just "Do you know that the prime gap is small even at $$$10^9$$$?".

Maybe it makes sense to put it in Starters since they are meant to be "educational" contests, but it still feels out of place.

I think anyone who solved this problem before can solve today's sum of Xor in 2-3 minutes

Today's E (LENGTHX) , its editorial was based on segment trees , any suggestions where to learn seg trees from ?

For xor sum , to prove all even $$$i \gt 4$$$ and $$$i \lt NM - 2$$$ , $$$F[i] = 0 $$$ , you can first construct $$$K = 6.$$$ However , it may get confusing when many $$$1s$$$ have been filled , to solve that case , observe that You can invert all $$$1s$$$ to $$$0$$$ and $$$0s$$$ to $$$1$$$ , and $$$F[i]$$$ remains same. Hence the case $$$K = 6$$$ is same as $$$K = NM - 6$$$ .

include <bits/stdc++.h>

using namespace std;

int main() { int t; cin >> t; while (t--) { int n; cin >> n; vector v(n); int y = 0; for (int i = 0; i < n; ++i) { cin >> v[i]; y = y | v[i]; }

for (int i = 31; i >= 0; i--) {
        if ((y & (1 << i)) == 0) {
            for (int j = 0; j < n; j++) {
                if (((v[j])> (pow(2,i)))) {
                    v[j] = -1;
                }
            }
        }
    }
    int a = count(v.begin(), v.end(), -1);
    cout << a << "\n";
}
return 0;

}this code is for 4th que of div4 in codechef(array removal) and it got accepted in codechef but this code gives wrong output for the input(n=4) {2,8,9,10}

are u gonna do anything about wrong submissions that got accepted for array removal problem,it had massive impact in rankings of div2

Cheaters Cheaters everywhere :

https://www.youtube.com/watch?v=lroJG3QAcRA

Today I was hoping to turn three star on Codechef but thanks to them

Sorry for mentioning you but the tester's code given for the problem Pairs Sum with Length x in today's contest does not work. Please fix it.
Submission link
mexomerf IceKnight1093.

Number Hunt Detailed Video Editorial

https://youtu.be/fhOLz-Or9NA