1、题目

 

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.

 

 

 

2、代码实现

 

 

public class Solution {public int findComplement(int num) {if (num <= 0)return 0;String result = "";while (num > 0) {result += num % 2;num = num / 2;}int length = result.length();int lastResult = 0;for (int i = 0; i < length - 1; ++i) {if (result.charAt(i) == '0') {int temp = (int) Math.pow(2, i);lastResult += temp;}	}return lastResult;}
}