Coloring cube

#include <iostream>
#include <vector>


using namespace std;


char getColor(int a){
    if (a==0) return 'R';
    if (a==1) return 'G';
    return 'B';
}

int main(){
    int n;
    cin >> n;
    vector<vector<vector<int>>> cub(n, vector<vector<int>>(n,vector<int>(n,-1)));
    cub[0][0][0] = 0;
    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            for(int l=0; l<n; l++){
                if(cub[i][j][l] == -1){
                    int pI, pJ, pL;
                    if(i==0 or cub[i-1][j][l]==-1) pI = -1;
                    else pI = cub[i-1][j][l];

                    if(j==0 or cub[i][j-1][l]==-1) pJ = -1;
                    else pJ = cub[i][j-1][l];

                    if(l==0 or cub[i][j][l-1]==-1) pL = -1;
                    else pL = cub[i][j][l-1];


                    if(pL != -1){
                        //mirar l-1
                        cub[i][j][l] = (pL +1)%3;

                    }
                    else if(pI != -1){
                        //mirar i-1
                        cub[i][j][l] = (pI +1)%3;

                    }
                    else if(pJ != -1){
                        //mirar j-1
                        cub[i][j][l] = (pJ +1)%3;

                    }
                }
                cout << getColor(cub[i][j][l]);
                if(l!=n-1) cout << " ";
            }
            cout << endl;

        }
        if(i!= n-1)cout <<endl;
    }



}

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