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

Problem

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&nbsp;<= 10^9

• 1 <= c&nbsp;<= 10^9

Solution (Java)

class Solution {
    public static int csb(int n) {
        int cnt = 0;
        while (n > 0) {
            int rsb = n & -n;
            n -= rsb;
            cnt++;
        }
        return cnt;
    }

    public int minFlips(int a, int b, int c) {
        int ans = 0;
        int or = a | b;
        ans += csb(or ^ c);
        int and = a & b;
        ans += csb(and & ~c);
        return ans;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).