Bit Manipulation-476. Number Complement

Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.

Note:

1. The given integer is guaranteed to fit within the range of a 32-bit signed integer.
2. You could assume no leading zero bit in the integer’s binary representation.

 

Example 1:

Input: 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.

 

Example 2:

Input: 1
Output: 0
Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.

class Solution {  
public:  
    int findComplement(int num) {  
        int n=0,cp,ans;  
        cp=num;  
        int m=1;  
        while(cp!=0){  
            cp=cp/2;m=m*2;  
        }  
        ans=m-1-num;  
        return ans;  
    }  
};