Sorting

#include <bits/stdc++.h>
using namespace std;
//#define int long long
int a[100], pos[100], n, ok;

void exchange(int i, int j){
//    if((i<0 || j<0 || i+1>=n || j+1>=n)){
//        cout << i << " " << j << "\n"; return;
//    }
    assert(!(i<0 || j<0 || i+1>=n || j+1>=n));
    swap(a[i], a[j]);
    swap(pos[a[i]], pos[a[j]]);
    ++i; ++j;
    swap(a[i], a[j]);
    swap(pos[a[i]], pos[a[j]]);
}

signed main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    int t; cin >> t;
    while(t--){
        cin >> n;
        ok=1;
        for(int i=0; i<n; ++i) cin >> a[i];
        for(int i=0; i<n; ++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{
                    exchange(n-4, n-2);
                }
            }else if(ind==i+1){
                if(i+4>=n) ok = 0;
                else{
                    exchange(i+1, i+3);
                }
            }else{
//                exchange(i, ind);
            }
        }
        if(ok) cout << "YES\n";
        else cout << "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