Split in Three

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define nl '\n'
#define io ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
const int mod = 1000000007;
const int mod2 = 998244353;

// change this
const int N = 105;

int n, arr[N], tar;

signed main() {
    io;
    cin >> n;
    tar = n*(n+1)/6;
    if (n == 3) {
        cout << "1 2 3" << nl;
        return 0;
    }

    if (n == 6) {
        cout << "2 1 3 1 3 2" << nl;
        return 0;
    }

    if (tar*3 != n*(n+1)/2) {
        cout << "IMPOSSIBLE" << nl;
        return 0;
    }
    
    for (int i=0; i<n; i++) arr[i] = 3;

    arr[n-1] = 1;
    arr[tar - n - 2] = 1;
    arr[n-2] = 2;
    arr[tar - (n-1) - 1] = 2;

    for (int i=0; i<n; i++) cout << arr[i] << ' ';
    cout << nl;
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: WRONG ANSWER

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 1, 2

Verdict: ACCEPTED

Test 7

Group: 1, 2

Verdict: ACCEPTED

Test 8

Group: 1, 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: WRONG ANSWER

Test 11

Group: 2

Verdict: WRONG ANSWER

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: WRONG ANSWER

Test 14

Group: 2

Verdict: WRONG ANSWER

Test 15

Group: 2

Verdict: ACCEPTED