LeetCode -- Number of 1 Bits

LeetCode -- Number of 1 Bits

題目描述：


Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).


For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should return 3.




本題依然屬於一道位運算的題目，輸入一個無符號的整數，判斷出1的個數。


思路：
對於整數n,從n開始對n和n-1做與運算然後賦值給n。即，n=n&n-1。直到n等於n為止。能做多少次運算就說明有多少個1。


實現代碼：

public class Solution {
    public int HammingWeight(uint n) {
        int count;
		for (count=0; n > 0 ; count++){
			n &= n-1;
		}
		return count;
    }
}