Problem:
Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.
Example 1:
Input: 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.
Example 2:
Input: 1
Output: 0
Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.
Note:
1. The given integer is guaranteed to fit within the range of a 32-bit signed integer.
2. You could assume no leading zero bit in the integer’s binary representation.
3. This question is the same as 1009: https://leetcode.com/problems/complement-of-base-10-integer/
思路：
Solution (C++):
int findComplement(int num) {
unsigned int mask = ~0;
while (num & mask) mask <<= 1;
return mask ^ ~num;
}
性能：
Runtime: 0 ms Memory Usage: 5.9 MB
思路：
Solution (C++):
性能：
Runtime: ms Memory Usage: MB
