461. Hamming Distance

The Hamming distance between two integers is the number of positions at which the corresponding bits are different.

Given two integers x and y, calculate the Hamming distance.

Note:
0 ≤ x, y < 231.

Example:

Input: x = 1, y = 4

Output: 2

Explanation:
1   (0 0 0 1)
4   (0 1 0 0)
       ↑   ↑

The above arrows point to positions where the corresponding bits are different.
含义：求两个数字的汉明距离
思路：先进行按位易或运算，不同的位结果为1，然后计算1个个数

    public int hammingDistance(int x, int y) {
         // return Integer.bitCount(x^y);       
          int res = 0, exc = x ^ y;
        // for (int i = 0; i < 32; ++i) {
        //     res += (exc >> i) & 1;
        // }
        
        while (exc!=0) {
            ++res;
            exc &= (exc - 1); //消除最后一位1
        }        
        return res;
    }