201. Bitwise AND of Numbers Range

Medium (Trung bình) Python 🔗 Xem trên LeetCode

📋 Đề Bài

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

 

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

 

Constraints:

  • 0 <= left <= right <= 231 - 1

🧠 Thuật Toán & Kỹ Thuật

Bit Manipulation (Thao tác bit)
⏱️ Thời gian O(n)
💾 Không gian O(1)

💻 Lời Giải

Python 0201-bitwise-and-of-numbers-range.py
class Solution:
    def rangeBitwiseAnd(self, left: int, right: int) -> int:
        cnt = 0
        
        while left != right:
            left >>= 1
            right >>= 1
            cnt += 1
            
        return left << cnt