Leetcode the number of '1' bit

计算无符号整形数中 the number of ‘1’ bit,
这道题很基础，用到几个运算符，&，>>>

第一种利用java函数法

/*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.*/public class Solution {    // you need to treat n as an unsigned value    public int hammingWeight(int n) {        return Integer.bitCount(n);      }}

接下来两种：

public class Solution {    // you need to treat n as an unsigned value    public int hammingWeight(int x) {        int count = 0;        while(n != 0) {        count += n&1;        n = n>>>1;    }    return count;    }}

public class Solution {    // you need to treat n as an unsigned value    public int hammingWeight(int x) {    int count = 0;        while(n != 0) {            if(n%2 != 0) count ++;            n = n>>>1;        }        return count;    }}

一天一题（虽然很菜，但要坚持嘛）

参考资料：

http://15838341661-139-com.iteye.com/blog/1642525