Bitwise AND of Numbers Range
Given two integers left and right that represent the range [left, right], return the bitwise AND of all numbers in this range, including both left and right.
Example 1
Input
left = 5 right = 7
Output
4
Explanation
The numbers in the range are:
5 = 101
6 = 110
7 = 111
Their bitwise AND is:
101
110
111
---
100
So the answer is 4.
Example 2
Input
left = 0 right = 0
Output
0
Explanation
The range contains only 0, so the result is 0.
Constraints
Hints:
Hint 1
Think about what happens to the common leading bits of all numbers between left and right.
Hint 2
Any bit that changes somewhere in the range will become 0 in the final AND.
Author & Technical Reviewer
Technically reviewed by: ExamAdda Technical Review Team
Technical Reviewers, ExamAdda
Software engineers at ExamAdda who check every article's definitions, complexity claims and code examples before and after publishing.
Published
Aug 23, 2026
Last updated
Aug 23, 2026
Content Verification Methodology
Definitions and complexity claims were checked against authoritative computer-science references. Code examples were compiled and tested with standard, boundary and edge-case inputs.
Expected Output