Given a positive integer num, output its complement number. The complement strategy is to flip the bits of its binary representation.
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:
The given integer num is guaranteed to fit within the range of a 32-bit signed integer. num >= 1 You could assume no leading zero bit in the integer’s binary representation. This question is the same as 1009: https://leetcode.com/problems/complement-of-base-10-integer/
public class Solution {
public int FindComplement(int num) {
int sum = 0;
for(int i=0;i<32 && num != 0;i++){
sum+=(int)Math.Pow(2,i)*((num&1)^1);
num=num>>1;
}
return sum;
}
}Time Complexity: O(logn) which corresponds to the number of bits in the number.
Space Complexity: O(1)
