1356. Sort Integers by The Number of 1 Bits java

https://leetcode.com/problems/sort-integers-by-the-number-of-1-bits/?envType=study-plan&id=programming-skills-i 

Sort Integers by The Number of 1 Bits - LeetCode

class Solution {
    public int[] sortByBits(int[] arr) {
        Integer[] a = new Integer[arr.length];
        for (int i = 0; i < a.length; i++) {
            a[i] = arr[i];
        }
        // Arrays.sort(a, (i, j) -> Integer.bitCount(i) != Integer.bitCount(j) ? Integer.bitCount(i) - Integer.bitCount(j) : i - j);
        Arrays.sort(a, Comparator.comparing(i -> Integer.bitCount(i) * 10000 + i));
        for (int i = 0; i < a.length; i++) {
            arr[i] = a[i];
        }
        return arr;
    }
}

https://st-lab.tistory.com/243

자바 [JAVA] - Comparable 과 Comparator의 이해

# TODO

람다식

https://tourspace.tistory.com/9

Java 8 Comparator

 

https://stackoverflow.com/questions/21970719/java-arrays-sort-with-lambda-expression