## 题目描述：

LeetCode 476. Number Complement

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.
```

## 题目大意：

1. 给定正数确保是32位带符号整数。
2. 可以假设整数的二进制表示不包含前导0。

## Python代码：

``````class Solution(object):
def findComplement(self, num):
"""
:type num: int
:rtype: int
"""
mask = (1 << 1 + int(math.log(num, 2))) - 1
``````

## Python代码：

``````class Solution(object):
def findComplement(self, num):
"""
:type num: int
:rtype: int
"""
return int(''.join(str(1 - int(x)) for x in bin(num)[2:]), 2)
``````

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