40. 3진법 뒤집기

 

public class Solution {
    public int solution(int n) {
        long answer = 0;
        int answer2 = 0;
        long num = 1;
        int i = 0;
        
        // 3진법
        while(true)
        {                        
            answer += (n % 3) * num;
            
            n = n / 3;
            num = num * 10;
            
            i++;
            if (n < 1) break;
        }
        
        num = 1;
        for (int j = 0; j < i - 1; ++j)
        {
            num *= 3;
        }
        
  		// 10진법      
        while(true)
        {
            answer2 += (int)((answer % 10) * num);
            answer = answer / 10;
            num = num / 3;
            if (num < 1) break;
        }
               
        return answer2;
    }