一、题目

Given 3 positives numbers a, b and c. Return the minimum flips required in some bits of a and b to make ( a OR b == c ). (bitwise OR operation).
Flip operation consists of change any single bit 1 to 0 or change the bit 0 to 1 in their binary representation.

Example 1:

Input: a = 2, b = 6, c = 5
Output: 3
Explanation: After flips a = 1 , b = 4 , c = 5 such that (a OR b == c)
Example 2:

Input: a = 4, b = 2, c = 7
Output: 1
Example 3:

Input: a = 1, b = 2, c = 3
Output: 0

Constraints:

1 <= a <= 10^9
1 <= b <= 10^9
1 <= c <= 10^9

二、题解

class Solution {
public:int minFlips(int a, int b, int c) {int res = 0;for(int i = 0;i < 30;i++){int abit = (a >> i) & 1;int bbit = (b >> i) & 1;int cbit = (c >> i) & 1;if(cbit == 1 && abit == 0 && bbit == 0) res++;else if(cbit == 0 && abit == 1 && bbit == 1) res += 2;else if(cbit == 0 && (abit == 1 || bbit == 1)) res++;}return res;}
};