179. Largest Number

class Solution {
    
    private class numComparator implements Comparator<String> {
        @Override
        
        public int compare(String a, String b) {
            String one = a + b;
            String two = b + a;
            
            return two.compareTo(one);
        }
    }
   
    public String largestNumber(int[] nums) {
        String[] n = new String[nums.length];
        
        for (int i = 0; i < nums.length; i++) {
            n[i] = String.valueOf(nums[i]);
        }
        
        Arrays.sort(n, new numComparator());
        
        if (n[0].equals("0")) {
            return "0";
        }
        
        String ans = "";
        
        for (String s : n) {
            ans = ans + s;
        }
        
        return ans;
        
    }
}

Runtime: 4 ms, faster than 98.02% of Java online submissions for Largest Number.
Memory Usage: 38.9 MB, less than 28.23% of Java online submissions for Largest Number.

보자마자 comparator 만들어야 한다고 생각
하지만 어떻게 만드는지 모른다는 것을 깨달음^^

그래서 과거 수업 (100mg)와 루션이 (12000000mg) 참고했읍니다^^