# LeetCode - 0476. Number Complement
### 題目網址：https://leetcode.com/problems/number-complement/
###### tags: `LeetCode` `Easy` `位元運算` `位元遮罩（Bit Mask）`

/*
    -LeetCode format-
    Problem: 476. Number Complement
    Difficulty: Easy
    
    by Inversionpeter
*/



class Solution {
public:
    int findComplement(int num) {
        unsigned leftMost = 1 << 31;
        while (leftMost) {
            if (leftMost & num)
                break;
            leftMost >>= 1;
        }
        return (~num) & (leftMost - 1);
    }
};