LeetCode-Number of 1 Bits

##题目

####Number of 1 Bits

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.

####Credits:
Special thanks to @ts for adding this problem and creating all test cases.

##解题思路
该题是判断一个数的二进制中1的个数，我们可以通过不断移位，然后判断最后一个数的思想，分别对每位进行判断，如果为1，则将个数+1。最后即可得到1的总个数。

##算法代码
代码采用JAVA实现：

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public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int res=0;
        for(int i=0;i<=31;i++)
	    {
	    	if((n & 1)==1)
	    		res++;
	    	n=n>>1;
	    }
	    return res;
    }
}