package org.programmers;

import java.util.Arrays;

import java.util.ArrayList;

public class Level_3 {

public static void main(String[] args) {

System.out.println(solution(6));

System.out.println(solution(7));

System.out.println(solution(8));

System.out.println(solution(9));

}

//-- 해당 숫자가 124에 해당하는지 확인한다.

public static int is_124(int num) {

int x,y;

do {

x = num % 10;

if ( x != 1 && x !=2 && x !=4) {

return -1;

}

num = num / 10;

} while (num > 0);

return 1;

}

public static String solution(int n) {

String answer = "";

int num = 1;

ArrayList<Integer> allowedNums = new ArrayList<>();

while (allowedNums.size() != n) {

if (is_124(num) == 1) {

allowedNums.add(num);

}

num++;

if (num > 100) break;

}

answer = Integer.toString(allowedNums.get(n-1));

return answer;

}

}