476. Number Complement

Problem

Tags: Bit Manipulation

The complement of an integer is the integer you get when you flip all the 0's to 1's and all the 1's to 0's in its binary representation.

• For example, The integer 5 is "101" in binary and its complement is "010" which is the integer 2.

Given an integer num, return its complement.

Example 1:

Input: num = 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: num = 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.

Constraints:

• 1 <= num < 2^31

Note: This question is the same as 1009: https://leetcode.com/problems/complement-of-base-10-integer/

Code

C

// 476. Number Complement (2/26/53959)
// Runtime: 0 ms (93.33%) Memory: 5.43 MB (60.00%) 

int findComplement(int num) {
    return ~num & (0xFFFFFFFF >> __builtin_clz(num)); 
}