Complement of Base 10 Integer

Similar Problems:

- Tag: #bitmanipulation

Every non-negative integer N has a binary representation. For example, 5 can be represented as “101” in binary, 11 as “1011” in binary, and so on. Note that except for N = 0, there are no leading zeroes in any binary representation.

The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1. For example, the complement of “101” in binary is “010” in binary.

For a given number N in base-10, return the complement of it’s binary representation as a base-10 integer.

Example 1:

Input: 5 Output: 2 Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.

Example 2:

Input: 7 Output: 0 Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.

Example 3:

Input: 10 Output: 5 Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.

Note:

- 0 <= N < 10^9

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

- Solution:

// Blog link: https://code.dennyzhang.com/complement-of-base-10-integer // Basic Ideas: bit map // Complexity: Time O(1), Space O(1) func bitwiseComplement(N int) int { if N == 0 { return 1 } k := 1 for k <= N { k = k*2 } k = k-1 return ^N & k }