func_code_string: #include <bits/stdc++.h>   using namespace std;   void make_unique(vector<long long> vec) {     sort((vec).begin(), (vec).end());     vec.resize(unique((vec).begin(), (vec).end()) - vec.begin());   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int t;     cin >> t;     while (t--) {       long long k, n, m, i, j, flag = 0, count = 0, move = 0;       string s;       cin >> n;       long long A[n];       vector<long long> v;       for (i = 0; i < n; i++) cin >> A[i];       long long freq[51] = {0};       for (i = 0; i < n; i++) {         freq[A[i]]++;       }       long long maxf = freq[0];       long long pos = 0;       vector<long long> sum(105, 0);       for (i = 0; i <= n; i++) {         for (j = i; j <= n; j++) {           if (i == j)             sum[i + j] += freq[i] / 2;           else {             sum[i + j] += min(freq[i], freq[j]);           }         }       }       cout << *max_element((sum).begin(), (sum).end()) << endl;     }     return 0;   }   