func_code_string: #include <bits/stdc++.h>   using namespace std;   struct custom_hash {     static uint64_t splitmix64(uint64_t x) {       x += 0x9e3779b97f4a7c15;       x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;       x = (x ^ (x >> 27)) * 0x94d049bb133111eb;       return x ^ (x >> 31);     }     size_t operator()(uint64_t x) const {       static const uint64_t FIXED_RANDOM =           chrono::steady_clock::now().time_since_epoch().count();       return splitmix64(x + FIXED_RANDOM);     }   };   long long getPairsCount(int arr[], int n, long long sum) {     unordered_map<int, int, custom_hash> m;     for (int i = 0; i < n; i++) m[arr[i]]++;     long long twice_count = 0;     for (int i = 0; i < n; i++) {       twice_count += m[sum - arr[i]];       if (sum - arr[i] == arr[i]) twice_count--;     }     return twice_count / 2;   }   int main() {     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       int ara[n];       long long sum = 0;       for (int i = 0; i < n; i++) {         cin >> ara[i];         sum += ara[i];       }       sum *= 2;       if (sum % n) {         cout <<  0 n ;         continue;       }       cout << getPairsCount(ara, n, sum / n) << endl;     }   }   