Sorting

#include <bits/stdc++.h>

using namespace std;

#define f first
#define s second

typedef long long ll;
typedef pair<int,int> pi;

vector<int> nums, pos;
////{a-1, a}, {b-1,b}
//void sw(int a, int b){
//    swap(nums[pos[a]], nums[pos[b]]);
//    swap(pos[a], pos[b]);
//    swap(nums[pos[a-1]], nums[pos[b-1]]);
//    swap(pos[a-1], pos[b-1]);
//}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
    int t; cin >> t;
    while(t--){
        int n; cin >> n;
        nums.resize(n+1), pos.resize(n+1);
        for(int i = 1; i <= n; i++) cin >> nums[i];
        for(int i = 1; i <= n; i++) pos[nums[i]] = i;
        int n2 = n;
//        for(; n2 > 4; n2--){
//            if(pos[n2] == n2) continue;
//            if(pos[n2] > 3){
//                sw(n2,nums[2]);
//            }
//            sw(n2, nums[n2]);
//        }
        bool good = 1;
        for(int i = 1; i <= n2; i++){
            if(pos[i] != i) good = 0;
        }
        if(n2 == 4){
            if(nums[1] == 3 &&
               nums[2] == 4 &&
               nums[3] == 1 &&
               nums[4] == 2
            ){
                good = 1;
            }
        }
        if(n > 4) good = 1;
        if(good) cout << "YES\n";
        else cout << "NO\n";
    }
    return 0;
}

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