Hi!
I have two really similar submissions to problem (https://codeforces.me/contest/1266/problem/E)
https://codeforces.me/contest/1266/submission/67209030 (**WA version**)
https://codeforces.me/contest/1266/submission/67209163 (**AC version**)
The WA version has the following line:
long long ans = accumulate( a.begin(), a.end(), 0, [] (long long a, long long b) { return a + b; } );
With this simple change on this specific line I got it accepted.
long long ans = accumulate( a.begin(), a.end(), 0ll, [] (long long a, long long b) { return a + b; } );
Why the zero of the WA version does not seem to be converted to long long?