3xBinary Type Multiple

#include <iostream>
#include <string>
#include <cstdio>

using namespace std;

long long k;            ///finding the least multiple of this number

int divisibility(string n, int l)
{
    long long a;
    a = 0;
    for(int i = 0; i < l; i++){
        a = a*10 + (n[i] - '0');
        a = a % k;
    }
    return !a;          ///return 1 if a == 0, return 0 if a != 0
}

int main()
{
    int i, l, n3, n0, j, ind_of_3;
    string num;

    while(scanf("%lld", &k) == 1){
        num.push_back('3');
        n3 = 1;         ///number of 3s
        n0 = 0;         ///number of 0s
        l = 1;          ///length of number
        ind_of_3 = 0;   ///index of last 3
        while(1){
            if(divisibility(num, l)){
                printf("%d %d %d\n", l, n3, n0);
                break;
            }

            if(l == n3){
                num.push_back('0');
                l++;
                n0++;
                j = l-1;
                for(i = 1; i < j; i++){
                    num[i] = '0';
                    n0++;
                    n3--;
                }
                ind_of_3 = 0;
            }
            else{
                ind_of_3++;
                num[ind_of_3] = '3';
                n3++;
                n0--;
            }
        }
        num.erase(num.begin(), num.end());
    }
    return 0;
}