Leetcode #2980: Check if Bitwise OR Has Trailing Zeros
In this guide, we solve Leetcode #2980 Check if Bitwise OR Has Trailing Zeros in Python and focus on the core idea that makes the solution efficient.
You will see the intuition, the step-by-step method, and a clean Python implementation you can use in interviews.
Problem Statement
You are given an array of positive integers nums. You have to check if it is possible to select two or more elements in the array such that the bitwise OR of the selected elements has at least one trailing zero in its binary representation.
Quick Facts
- Difficulty: Easy
- Premium: No
- Tags: Bit Manipulation, Array
Intuition
The problem structure lets us track state with bitwise operations.
Bit operations are constant time and avoid extra memory.
Approach
Apply XOR/AND/OR and shifts to maintain the required invariant.
Aggregate the result in a single pass.
Steps:
- Identify a bitwise invariant.
- Combine values with bit operations.
- Return the aggregated result.
Example
Input: nums = [1,2,3,4,5]
Output: true
Explanation: If we select the elements 2 and 4, their bitwise OR is 6, which has the binary representation "110" with one trailing zero.
Python Solution
class Solution:
def hasTrailingZeros(self, nums: List[int]) -> bool:
return sum(x & 1 ^ 1 for x in nums) >= 2
Complexity
The time complexity is , where is the length of the array. The space complexity is .
Edge Cases and Pitfalls
Watch for boundary values, empty inputs, and duplicate values where applicable. If the problem involves ordering or constraints, confirm the invariant is preserved at every step.
Summary
This Python solution focuses on the essential structure of the problem and keeps the implementation interview-friendly while meeting the constraints.