Codeforces

627B.cpp

#include<bits/stdc++.h>
 
#define endl "\n";
using namespace std;
typedef long long ll;
 
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int t;
  cin >> t;
  for (; t--;) {
    int n;
    cin >> n;
    vector<int> vc;
    vector<pair<int, int>> arr;
    for (int i = 0; i < n; i++) {
      int x;
      cin >> x;
      vc.push_back(x);
      arr.push_back(make_pair(x, i));
    }
    sort(arr.begin(), arr.end());
    bool found = false;
    for (int i = 0; i < vc.size(); i++) {
      int idx = lower_bound(arr.begin(), arr.end(), make_pair(vc[i], 0)) - arr.begin();
      int idx2 = upper_bound(arr.begin(), arr.end(), make_pair(vc[i], 5001)) - arr.begin();
      if (arr[idx].first == vc[i]) {
        if (arr[idx2 - 1].second != i) {
          if (abs(i - arr[idx2- 1].second) > 1) {
            found = true;
            cout << "YES" << endl;
            break;
          }
        }
      }
    }
    if (!found)cout << "NO" << endl;
  }
}