LeetCode-1318. Minimum Flips to Make a OR b Equal to c

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​​

​​题解：​​

class Solution {
public:
    int minFlips(int a, int b, int c) {
        int res = 0;
        for (int i = 0; i < 32; i++) {
            int k1 = a & (1 << i);
            int k2 = b & (1 << i);
            int k3 = c & (1 << i);
            if (k3 == 0) {
                if (k1 != k3) {
                    res++;
                }
                if (k2 != k3) {
                    res++;
                }
            }
            else {
                if (k1 != k3 && k2 != k3) {
                    res++;
                }
            }
        }
        return res;
    }
};