1012. Numbers With Repeated Digits 至少有 1 位重复的数字

作者： 负雪明烛 id： fuxuemingzhu 个人博客： https://fuxuemingzhu.cn/

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题目地址：https://leetcode.com/problems/complement-of-base-10-integer/

题目描述

Every non-negative integer N has a binary representation. For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on. Note that except for N = 0, there are no leading zeroes in any binary representation.

The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1. For example, the complement of "101" in binary is "010" in binary.

For a given number N in base-10, return the complement of it’s binary representation as a base-10 integer.

Example 1:

Input: 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.

Example 2:

Input: 7
Output: 0
Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.

Example 3:

Input: 10
Output: 5
Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.

Note:

1. 0 <= N < 10^9

题目大意

求一个数的补码。

解题方法

很简单一个作弊方法，直接求二进制，然后把1改成0，把0改成1即可。

Python代码如下：

class Solution(object):
    def bitwiseComplement(self, N):
        """
        :type N: int
        :rtype: int
        """
        return int("".join(map(lambda x :"0" if x == "1" else "1", bin(N)[2:])), 2)

日期

2019 年 3 月 21 日 —— 好久不刷题，重拾有点难