[LintCode] Flip Bits

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

Example

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

Note

Both n and m are 32-bit integers.

 

Normal Solution:

class Solution {
public:
    /**
     *@param a, b: Two integer
     *return: An integer
     */
    int bitSwapRequired(int a, int b) {
        // write your code here
        int cnt = 0;
        for(int i = 0;i < 32;i++){
            if((a&1) != (b&1)) cnt++;
            a >>= 1;
            b >>= 1;
        }
        return cnt;
    }
};

Use STL:

#include <bitset>
class Solution {
public:
    /**
     *@param a, b: Two integer
     *return: An integer
     */
    int bitSwapRequired(int a, int b) {
        // write your code here
        bitset<32> bitvec_a(a), bitvec_b(b);
        int cnt = 0;
        for(int i = 0;i < 32;i++)
            if(bitvec_a[i] != bitvec_b[i])
                cnt++;
        return cnt;
    }
};