Distinct sums

#include <bits/stdc++.h>

using namespace std;

typedef int64_t ll;
typedef uint64_t ull;

#define M 1000000007

int main() {
    ull n;
    cin >> n;
    if (n%2==1) {
        cout << "IMPOSSIBLE" << endl;
        return 0;
    }

    for (ull i = 0; i < n/2; i++) {
        for (ull j = 0; j < n; j++) {
            if (j<n-i) {
                cout << 0;
            } else {
                cout << 1;
            }
        }
        cout << endl;
    }

    for (ull i = n/2; i < n; i++) {
        for (ull j = 0; j < n; j++) {
            if (j<n-i) {
                cout << 1;
            } else {
                cout << 2;
            }
        }
        cout << endl;
    }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: ACCEPTED

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: ACCEPTED