476. Number Complement - easy
문제
Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.
제한사항
- The given integer is guaranteed to fit within the range of a 32-bit signed integer.
- You could assume no leading zero bit in the integer’s binary representation.
입출력 예
1
2
3
4
5
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.
1
2
3
4
5
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.
풀이
- Bit Manipulate
1
2
3
4
5
6
7
func findComplement(num int) int {
mask := ^0
for ; (num & mask) > 0 ; mask <<= 1 {}
return (^mask) ^ num;
}