func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int s[n + 1];     s[0] = 0;     for (int i = 1; i <= n; i++) cin >> s[i];     int dp[n + 1][n + 1];     memset(dp, 0, sizeof(dp));     int ans = 0;     for (int i = 1; i <= n; i++) {       int prev = 0;       for (int j = 0; j < i; j++) {         dp[i][j] = dp[j][prev] + 1;         if (s[i] == s[j]) prev = j;         ans = max(ans, dp[i][j]);       }     }     cout << ans << endl;     return 0;   }   