Sorting

#include <bits/stdc++.h>
using namespace std;
//#define int long long

signed main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    int t; cin >> t;
    while(t--){
        int n; cin >> n;
        int a[n], pos[n], ok=1;
        for(int& i : a) cin >> i;
        for(int& i : a) --i;
        for(int i=0; i<n; ++i){
            pos[a[i]] = i;
        }
        for(int i=0; i<n && ok; ++i){
            int ind = pos[i];
            if(ind==i) continue;
            if(ind==n-1){
                if(n-4<i) ok = 0;
                else{
                    swap(a[n-4], a[n-2]);
                    swap(pos[a[n-4]], pos[a[n-2]]);
                    swap(a[n-3], a[n-1]);
                    swap(pos[a[n-3]], pos[a[n-1]]);
                }
            }else if(ind==i+1){
                if(i+4>=n) ok = 0;
                else{
                    swap(a[i+1], a[i+3]);
                    swap(pos[a[i+1]], pos[a[i+3]]);
                    swap(a[i+2], a[i+4]);
                    swap(pos[a[i+2]], pos[a[i+4]]);
                }
            }else{
                swap(a[i], a[ind]);
                swap(pos[a[i]], pos[a[ind]]);
                swap(a[i+1], a[ind+1]);
                swap(pos[a[i+1]], pos[a[ind+1]]);
            }
        }
        if(ok) cout << "YES\n";
        else cout << "NO\n";
    }

}

Test 1

Group: 1, 2

Verdict: RUNTIME ERROR

Test 2

Group: 2

Verdict: RUNTIME ERROR

Test 3

Group: 1, 2

Verdict: RUNTIME ERROR

Test 4

Group: 1, 2

Verdict: WRONG ANSWER