Flip Bits 181

Question

Determine the number of bits required to flip if you want to convert integer n to integer m.

Notice

Both n and m are 32-bit integers.

Example

Given n = 31 (11111), m = 14 (01110), return 2.

Solution

对a和b取^操作，如果a和b的某一位上不同则结果的那一位上为1，相同为0。然后只要依次看结果有几位1（不同）即可。

代码如下：

class Solution {
    /**
     *@param a, b: Two integer
     *return: An integer
     */
    public static int bitSwapRequired(int a, int b) {
        // write your code here
        int count = 0;
        for(int c = a ^ b; c != 0; c = c >>> 1){
            count += c & 1;
        }

        return count;
    }
};