Coloring cube

#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    const char c[] = "RGB";
    for (int z = 0; z < n; z++) {
        if (z) cout << "\n";
        for (int y = 0; y < n; y++)
            for (int x = 0; x < n; x++)
                cout << c[(x + y + z) % 3] << (x < n - 1 ? ' ' : '\n');
    }
}

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