Codeforce A. Milking cows

#include<iostream>#include<cstring>#include<cstdio>using namespace std; #define N 200005 long long int ans, cow[N], lose[N];  int main(int argc, char const *argv[]) {    int n;     /* freopen("in.c", "r", stdin); */     while(cin >> n)    {        ans = 0;         memset(lose, 0, sizeof(lose));         for(int i = 1;i <= n;i ++)        {            cin >> cow[i];             lose[i] = lose[i-1] + cow[i];             if(cow[i] == 0)                ans += lose[i];          }        cout << ans << endl;     }    return 0; }