func_code_string: #include <bits/stdc++.h>   using namespace std;   int xx[] = {0, 0, -1, 1}, yy[] = {-1, 1, 0, 0};   using ll = long long;   using ppi = pair<int, int>;   using ppl = pair<ll, ll>;   ll d[3001][3001];   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     int T;     cin >> T;     while (T--) {       int N;       cin >> N;       vector<int> v(N);       for (long long i = (0); i < (N); ++i) {         cin >> v[i];       }       memset(d, 0, sizeof(d));       for (int i = N - 1; 0 <= i; --i) {         d[i][v[i]] = 1;         if (i + 1 < N) {           for (long long x = (1); x <= (N); ++x) {             d[i][x] += d[i + 1][x];           }         }       }       ll ans = 0;       for (long long j = (1); j < (N - 2); ++j) {         for (long long k = (j + 1); k < (N - 1); ++k) {           ans += (d[0][v[k]] - d[j][v[k]]) * (d[k + 1][v[j]]);         }       }       cout << ans << ((char)10);     }     return 0;   }   