06_BitwiseAndOfANumber.py

# Question link - https://leetcode.com/problems/bitwise-and-of-numbers-range/?envType=study-plan-v2&envId=top-interview-150

class Solution:
    def rangeBitwiseAnd(self, left: int, right: int) -> int:
        # Sol3: Optimal Solution O(logn) with simple left and right
        # compartion
        i = 0
        while left != right:
            left = left >> 1
            right = right >> 1
            i += 1
        return left << i

        # Sol2: Better Approch - O(logn) , complex solution 
        # res = 0
        # for i in range(32):
        #     bit = (left >> i) & 1
        #     # If not 1 , skip 
        #     if not bit:
        #         continue 

        #     # Diff calculation 
        #     remain = left % (1 << (i + 1))
        #     diff = (1 << (i + 1)) - remain

        #     # Right - left < diff
        #     if right - left < diff:
        #         # Putting the 1 in output
        #         res = res | (1 << i)
        # return res 


        # Sol1: Brute Solution with O(n) 
        # res = 0
        # for i in range (left , right):
        #     res = res & i 

        # return res