Leetcode-Algorithms Number Complement(数字补码）

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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.

如题数字补码就是求本身的补码后return其十进制的数。二进制5 = 101（无视正负位的数->leading bit）其补码 010 = 2

class Solution(object):    def findComplement(self, num):        """        :type num: int        :rtype: int        """        return (1<<len("{0:b}".format(num)))-1 ^ num

首先将补位到和二进制带leading bits的num相同长度（10000…..）， -1后用^运算符补码.

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