Good Subarray

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

int t;

int main(){
    //freopen("goodsubarrays.in", "r", stdin);

    cin >> t;
    while(t--){
        int n;
        cin >> n;
        string s;
        cin >> s;
        ll sum = 0;
        unordered_map<ll, int> freq;
        freq[0] = 1;
        ll ans = 0;
        for(int i=0; i<n; i++){
            sum+=s[i]-'0';
            ll val = sum-(i+1);
            ans+=freq[val];
            freq[val]++;
        }
        cout << ans << '\n';
    }

    return 0;
}