문제

https://programmers.co.kr/learn/courses/30/lessons/12899#

풀이

function solution(n) {
    let result = [];
    let portion = n;
    let remain = 0;
    
    while (portion > 0) {
        remain = portion % 3;
        portion = Math.floor(portion / 3);
        
        switch(remain) {
            case 1 :
                result.push(1);
                break;
            case 2 :
                result.push(2);
                break;
            case 0:
                result.push(4);
                portion -= 1;
                break;
        }
    }
    
    return result.reverse().join('');
}

index로 규칙성 찾기
3의 배수로 나누어지는 예외 처리하기