LeetCode_476. Number Complement

476. Number Complement

Easy

Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.

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.

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.

package leetcode.easy;

public class NumberComplement {
	public int findComplement(int num) {
		int complement = 0;
		int pos = 0;
		while (num > 0) {
			if ((num & 1) == 0) {
				complement |= (1 << pos);
			}

			pos++;
			num >>>= 1;
		}

		return complement;
	}

	@org.junit.Test
	public void test() {
		System.out.println(findComplement(5));
		System.out.println(findComplement(1));
	}
}