CodeForces. 1333C Eugene and an array

1.Problem
https://codeforces.com/problemset/problem/1333/C

2.Idea
Keep tracking right most sum zero segment. 

3.Source

 int n;  
 map<ll, int> mp;  
 ll ans, sum;  
 int x, q;  
 int main()  
 {  
      cin >> n;  
      q = -1;  
      mp[0] = 0;  
      for (int i = 1; i <= n; i++)  
      {  
           cin >> x;  
           sum += x;  
           if (mp.count(sum)) {  
                q = max(q, mp[sum]);  
           }  
           ans += (i - q - 1);  
           mp[sum] = i;  
      }  
      cout << ans << endl;  
      return 0;  
 }