How do you solve Bitwise OR of Even Numbers in an Array on LeetCode?

Bitwise OR of Even Numbers in an Array (LeetCode #3688) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(1) space complexity. Key insight: Bitwise OR accumulates bits set to 1 from the numbers.

What is the time complexity of Bitwise OR of Even Numbers in an Array?

The optimal solution for Bitwise OR of Even Numbers in an Array runs in O(n) time and uses O(1) space. The complexity is O(n) because we only loop through the array once, updating the result in constant space.

What is the brute force solution for Bitwise OR of Even Numbers in an Array?

The brute force approach for Bitwise OR of Even Numbers in an Array is Brute Force, with O(n) time complexity and O(1) space complexity. Iterate through the array and check each number for evenness. If it's even, perform a bitwise OR operation with the result. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Bitwise OR of Even Numbers in an Array?

Bitwise OR of Even Numbers in an Array uses the following concepts: Array, Bit Manipulation, Simulation. The recommended patterns to study are: Bit Manipulation, Array.

What are the interview tips for Bitwise OR of Even Numbers in an Array?

Explain your thought process clearly. Discuss edge cases like no even numbers. Be prepared to optimize your solution.

What are common mistakes when solving Bitwise OR of Even Numbers in an Array?

Forgetting to check if a number is even. Not initializing the result variable correctly.

#3688

Bitwise OR of Even Numbers in an Array

Easy

ArrayBit ManipulationSimulationBit ManipulationArray

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n)	O(n)
Space	O(1)	O(1)

💡

Intuition

Time O(n)Space O(1)

Directly compute the bitwise OR of even numbers in a single pass through the array, maintaining a cumulative result.

⚙️

Algorithm

3 steps

1Step 1: Initialize a variable `result` to 0.
2Step 2: Loop through each number in the array.
3Step 3: If the number is even, update `result` with the bitwise OR of `result` and the number.

solution.py6 lines

1def bitwise_or_of_evens(nums):
2    result = 0
3    for num in nums:
4        if num % 2 == 0:
5            result |= num
6    return result

ℹ

Complexity note: The complexity is O(n) because we only loop through the array once, updating the result in constant space.

1Bitwise OR accumulates bits set to 1 from the numbers.
2Even numbers can be identified using modulus operation.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.