B. Mancala (Codeforces Round #478 (Div. 2))

#include <bits/stdc++.h>
using namespace std;
const int maxn = 14;
typedef long long ll;
ll a[maxn];
ll b[maxn];

int main(){
    for(int i =0 ;i < maxn;i++){
        cin >> a[i];
    }
    ll ans = -1;
    for(int i = 0;i < maxn;i++){
        for(int j = 0;j < maxn;j++) b[j] = a[j];
        b[i] = 0;
        int x = a[i] / maxn;
        int y = a[i] % maxn;
        for(int j = 0;j < maxn;j++)
            b[j] += x;
        for(int j = 1;j <= y;j++)
            b[(j+i)%maxn]++;
        ll sum = 0;
        for(int j = 0;j < maxn;j++)
            if(b[j]%2 == 0)
            sum += b[j];
        if(ans < sum)
            ans = sum;
    }
    cout << ans << endl;
    return 0;
}

B. Mancala