README.md

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

Solutions (Rust)

1. Bitwise Operator

impl Solution {
    pub fn min_flips(a: i32, b: i32, c: i32) -> i32 {
        let mut a = a;
        let mut b = b;
        let mut c = c;
        let mut ret = 0;

        while a > 0 || b > 0 || c > 0 {
            let d = a & 1;
            let e = b & 1;
            let f = c & 1;
            match (d << 2) + (e << 1) + f {
                0b001 | 0b010 | 0b100 => ret += 1,
                0b110 => ret += 2,
                _ => (),
            }
            a >>= 1;
            b >>= 1;
            c >>= 1;
        }

        ret
    }
}