[LeetCode one question per day] [Simple] 1356. Sort according to the number of 1 under the digital binary

[LeetCode one question per day] [Simple] 1356. Sort according to the number of 1 under the digital binary

1356. Sort according to the number of 1s in digital binary

1356. Sort according to the number of 1 in digital binary.
Algorithm idea: Array

topic:

java code

class Solution {
    
    
    public int[] sortByBits(int[] arr) {
    
    
		for (int i = 0; i < arr.length; i++) {
    
    
			arr[i] += Integer.bitCount(arr[i]) * 100000;//1的个数最多16位，两位数，所以使用100000来保存
            //使用nteger.bitCount(arr[i])来获取数二进制1的个数效率高,使用的是位运算
		}
		Arrays.sort(arr);//排序
		for (int i = 0; i < arr.length; i++) {
    
    
			arr[i] = arr[i] % 100000;//还原
		}
		return arr;
	}
}