Sorting

#include <bits/stdc++.h>
using namespace std;
 
int N, T;
int A[105];
map <int,bool> M;
 
void dfs() {
	int x=0;
	for (int i=0;i<N;i++) {
		x*=10;
		x+=A[i];
	}
	
	if (M[x]) return;
	M[x]=1;
	
	for (int i=3;i<N;i++) {
		for (int j=1;j<i-1;j++) {
			swap(A[j-1],A[i-1]);
			swap(A[j],A[i]);
			dfs();
			swap(A[j-1],A[i-1]);
			swap(A[j],A[i]);
		}
	}
}
 
int main() {
	for (N=1;N<=5;N++) {
		for (int i=0;i<N;i++) {
			A[i]=i+1;
		}
		dfs();
	}
	
	cin>>T;
	for (int i=1;i<=T;i++) {
		cin>>N;
		for (int j=1;j<=N;j++) {
			cin>>A[j];
		}
		for (;N>5;N--) {
			int x;
			for (x=1;A[x]!=N;x++);
			if (x==N) {
				continue;
			}
			if (x==N-1) {
				swap(A[N-4],A[N-3]);
				swap(A[N-3],A[N-2]);
				swap(A[N-2],A[N]);
				swap(A[N-1],A[N]);
				continue;
			}
			if (x==1) {
				swap(A[1],A[3]);
				swap(A[2],A[N-1]);
				swap(A[3],A[N]);
				swap(A[4],A[N-1]);
				continue;
			}
			swap(A[x-1],A[N-1]);
			swap(A[x],A[N]);
		}
		int x=0;
		for (int j=1;j<=N;j++) {
			x*=10;
			x+=A[j];
		}
		if (M[x]) {
			cout<<"YES\n";
		}
		else {
			cout<<"NO\n";
		}
	}
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED