Array Questions at Airbnb: What to Expect

Array questions make up nearly half of Airbnb’s technical interview problems (29 out of 64). This high frequency reflects how often arrays appear in real-world data processing—think user listings, booking dates, pricing tiers, or location coordinates. Mastering array manipulation is non-negotiable for passing their interviews.

What to Expect — Types of Problems

Airbnb’s array questions typically fall into three categories:

1. Two-Pointer and Sliding Window: Used for problems involving sorted arrays, subarrays, or sequences. Expect tasks like finding pairs with a target sum, removing duplicates in-place, or calculating maximum subarray sums.
2. Hash Map and Frequency Counting: Common when tracking occurrences, checking for duplicates, or solving anagram/pattern problems. You’ll often need to optimize lookups to O(1).
3. Interval Merging and Overlap: Airbnb deals heavily with date ranges and booking schedules. Problems often involve merging intervals, finding free slots, or detecting conflicts.

These problems test both your ability to write efficient code and your skill in handling edge cases, like empty inputs or overlapping boundaries.

How to Prepare — Study Tips with One Code Example

Focus on pattern recognition, not memorization. Practice each category until you can identify the approach within minutes. Always clarify input constraints and edge cases aloud. For coding, prioritize clean, readable implementations with clear variable names.

A key pattern is the two-pointer technique for finding a pair in a sorted array that sums to a target. Here’s how it works in three languages:

def two_sum_sorted(nums, target):
    left, right = 0, len(nums) - 1
    while left < right:
        current_sum = nums[left] + nums[right]
        if current_sum == target:
            return [left, right]
        elif current_sum < target:
            left += 1
        else:
            right -= 1
    return []

Recommended Practice Order

Start with foundational problems, then move to Airbnb-specific patterns:

1. Basic Manipulation: Reverse arrays, remove duplicates, binary search.
2. Two-Pointer & Sliding Window: Practice sum problems, subarray sums, and windowed maximums.
3. Hash Map Problems: Work on two-sum (unsorted), anagrams, and frequency counters.
4. Intervals: Merge intervals, insert intervals, find meeting conflicts.
5. Airbnb Tagged Questions: Solve actual problems from Airbnb’s question list to familiarize yourself with their style.

Consistency matters more than cramming. Solve 1-2 problems daily, focusing on clean code and optimal time complexity.

Practice Array at Airbnb