Description
Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive.
Example 1:
Input: [5,7]
Output: 4
Example 2:
Input: [0,1]
Output: 0
描述
给定范围 [m, n]，其中 0 <= m <= n <= 2147483647，返回此范围内所有数字的按位与（包含 m, n 两端点）。
示例 1:
输入: [5,7]
输出: 4
示例 2:
输入: [0,1]
输出: 0
思路
- 本题目考察位运算.
- 相当于求第一个数和最后一个数前缀相同的部分，后面不同的部分用0补齐.
# -*- coding: utf-8 -*- # @Author: 何睿 # @Create Date: 2019-01-20 21:06:34 # @Last Modified by: 何睿 # @Last Modified time: 2019-01-21 18:21:42 class Solution: def rangeBitwiseAnd(self, m, n): """ :type m: int :type n: int :rtype: int """ diff = 0 while m - n: diff += 1 m >>= 1 n >>= 1 return m << diff
源代码文件在这里.
