1、题目
Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.
Note:
The given integer is guaranteed to fit within the range of a 32-bit signed integer.
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;
}
}
