1318

1318. Minimum Flips to Make a OR b Equal to c (Medium)

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

Related Topics:
Bit Manipulation

Solution 1.

// OJ: https://leetcode.com/problems/minimum-flips-to-make-a-or-b-equal-to-c/
// Author: github.com/lzl124631x
// Time: O(1)
// Space: O(1)
class Solution {
public:
    int minFlips(int a, int b, int c) {
        int ans = 0;
        for (int i = 0; i < 31; ++i) {
            if ((c >> i) & 1) ans += ((a >> i) & 1) == 0 && ((b >> i) & 1) == 0;
            else ans += ((a >> i) & 1) + ((b >> i) & 1);
        }
        return ans;
    }
};