Sorting

#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define all(x) (x).begin(),(x).end()
#define pb push_back
 
signed main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int t; cin >> t;
  while(t--){
    int n; cin >> n;
    int a[n];
    for(int i = 0; i < n; ++i) {
      cin >> a[i];
    }
    if(n <= 3) {
      bool ok = 1;
      for(int i = 0; i < n; ++i) {
        ok &= a[i] == i + 1;
      }
      cout << (ok ? "YES\n" : "NO\n");
      continue;
    }
    if(n == 4) {
      array<int, 4> last = {a[0], a[1], a[2], a[3]};
      vector<array<int, 4>> poss;
      poss.pb({1, 2, 3, 4});
      poss.pb({3, 4, 1, 2});
      bool ok = 0;
      for(auto i : poss) {
        ok |= last == i;
      }
      cout << (ok ? "YES\n" : "NO\n");
      continue;
    }
    int ind = 0, sz = n;
    while(sz > 4) {
      int id = 0;
      if(a[n - 1] == 1) {
        swap(a[n - 1], a[n - 3]);
        swap(a[n - 2], a[n - 4]);
      } else if(a[ind + 1] == 1) {
        swap(a[ind + 1], a[ind + 3]);
        swap(a[ind + 2], a[ind + 4]);
      }
      for(int i = ind; i < n; ++i) {
        if(a[i] == 1) {
          id = i;
          break;
        }
      }
      if(id != ind) {
        swap(a[id], a[ind]);
        swap(a[id + 1], a[ind + 1]);
      }
      --sz;
      for(int i = ind + 1; i < n; ++i) {
        --a[i];
      }
      ++ind;
    }
    array<int, 4> last = {a[n - 4], a[n - 3], a[n - 2], a[n - 1]};
    vector<array<int, 4>> poss;
    poss.pb({1, 2, 3, 4});
    poss.pb({3, 4, 1, 2});
    poss.pb({4, 3, 2, 1});
    poss.pb({2, 1, 4, 3});
    poss.pb({2, 3, 1, 4});
    poss.pb({1, 4, 2, 3});
    bool ok = 0;
    for(auto i : poss) {
      ok |= last == i;
    }
    cout << (ok ? "YES\n" : "NO\n");
  }
}

Test 1

Group: 1, 2

Verdict: WRONG ANSWER

Test 2

Group: 2

Verdict: WRONG ANSWER

Test 3

Group: 1, 2

Verdict: WRONG ANSWER

Test 4

Group: 1, 2

Verdict: WRONG ANSWER