LeetCode 201. Bitwise AND of Numbers Range.jpg
LeetCode 201. Bitwise AND of Numbers Range
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
