Problem: 191. 位1的个数
参考
public class Solution { // you need to treat n as an unsigned value public int hammingWeight(int n) { int res = 0; while (n != 0) { res += 1; n &= n - 1;// 把最后一个出现的 1 改为 0,和 lowbit 有异曲同工之妙 } return res; } }