Permutations

#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n;
    cin >> n;
    if(n==1)cout << "1" << endl;
    else{
    if(n<4)cout << "NO SOLUTION" << endl;
    else{
            if(n==4){
            cout << "3 1 4 2" << endl;
            }else{
        int par;
        int npar;
        if(n%2==0){
            par=n;
            npar=n-1;
        }else{
        par=n-1;
        npar=n;
        }
        for(int i=par;i>1;i-=2){
            cout << i << " ";
        }
        for( int i=npar;i>1;i-=2){
            cout << i << " ";
        }
        cout << "1" << endl;
    }
    }
    }
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED