Leetcode 201. Bitwise AND of Numbers Range

Problem Statement :

Given two integers left and right that represent the range [left, right]. return the bitwise AND of all numbers in this range, inclusive.

Examples :

Example 1

Input: left = 5, right = 7
Output: 4

Example 2

Input: left = 0, right = 0
Output: 0

Example 3

Input: left = 1, right = 2147483647
Output: 0

Constrains :

0 <= left <= right <= 231 - 1

Explanation

  Revision

Solution (Py3) :

    class Solution:
      def rangeBitwiseAnd(self, left: int, right: int) -> int:
          cnt = 0
          while left != right:
              left >>= 1
              right >>= 1
              cnt += 1
          return left << cnt