191. 位1的个数

输入: 11
输出: 3
解释: 整数 11 的二进制表示为 00000000000000000000000000001011

输入: 128
输出: 1
解释: 整数 128 的二进制表示为 00000000000000000000000010000000

public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int count = 0;
        for (int i = 0; i < 32; i++) {
            int tmp = n & 1;
            if (tmp == 1) {
                count++;
            }
            n >>= 1;
        }
        return count;
    }
}