Interview questions

Find earliest supporting dependency version

Companies: OpenAI

Binary Search

Last reported Aug 2025

Find the Safest Path in a Grid

Compute each cell's Manhattan distance to the nearest thief, then find a path from (0,0) to (n-1,n-1) that maximizes the minimum of those distances along…

Companies: Google, Meta, Uber

Array · Binary Search · Breadth-First Search · Heap (Priority Queue)

Last reported May 2025

Median of Two Sorted Arrays

Find the median of two sorted arrays in O(log(m+n)) time by using binary search to partition the arrays so the left half contains the correct…

Companies: Amazon, Bloomberg, eBay, Goldman Sachs +5

Array · Binary Search · Divide and Conquer

Last reported Apr 2025

Search Insert Position

Given a sorted array of distinct integers and a target, return the index where the target is found or the index where it should be…

Companies: Bloomberg, Google, Grammarly, Meta

Array · Binary Search

Last reported Jan 2025

Shortest Subarray with Sum at Least K

Find the length of the shortest contiguous subarray whose sum is at least k, or return -1 if none exists. Because nums can contain negative…

Companies: Meta

Array · Binary Search · Heap (Priority Queue) · Monotonic Queue

Last reported Jan 2025

132 Pattern

Determine whether the array contains indices i < j < k such that nums[i] < nums[k] < nums[j] (a "132" subsequence). With n up to…

Companies: DoorDash

Array · Binary Search · Monotonic Stack · Ordered Set

Avoid Flood in The City

Assign dry operations on zero days so that no lake is rained on while already full: given a sequence where rains[i]>0 fills a lake and…

Companies: MongoDB

Array · Binary Search · Greedy · Hash Table

Binary Searchable Numbers in an Unsorted Array

Given an unsorted array, count the elements that are "binary searchable" — values that would be found by standard binary search without sorting, meaning every…

Companies: Uber

Array · Binary Search · Monotonic Stack · Stack

Block Placement Queries

Support inserting obstacles at points on the nonnegative number line and, for each query, determine whether there exists any obstacle-free interval of length >= sz…

Companies: Hudson River Trading, Roblox, TikTok

Array · Binary Indexed Tree · Binary Search · Ordered Set

Building Boxes

Place n unit cubes into stacks on an n×n floor with the rule that a cube can be stacked only if the supporting cube's four…

Companies: Adobe

Binary Search · Greedy · Math

Heaters

Given positions of houses and heaters on a line, find the minimum uniform radius R such that every house is within distance R of some…

Companies: Anduril

Array · Binary Search · Sorting · Two Pointers

Longest Increasing Subsequence

Given an array of integers, return the length of the longest strictly increasing subsequence; the core challenge is to compute this efficiently—naive DP is O(n^2)…

Companies: PayPal

Array · Binary Search · Dynamic Programming · Longest Increasing Subsequence

Minimize max L1 radius with k centers in 1D

Companies: Atlassian

Binary Search · Greedy

Minimum Operations to Reduce X to Zero

Remove elements from either end to make the sum of removed elements equal x; equivalently, find the longest contiguous subarray whose sum equals total(nums) -…

Companies: Bloomberg

Array · Binary Search · Hash Table · Prefix Sum

Minimum Removals to Balance Array

Given nums and k, remove the fewest elements so the remaining array has max ≤ k * min. Equivalently, find the largest subset of numbers…

Companies: Salesforce

Array · Binary Search · Sliding Window · Sorting

Minimum Sum of Squared Difference

Given two arrays and up to k1 and k2 unit +/-1 edits, minimize the sum of (nums1[i]-nums2[i])^2 by optimally allocating k = k1+k2 operations to…

Companies: Google

Array · Binary Search · Greedy · Heap (Priority Queue)

Number of Flowers in Full Bloom

Given a list of closed time intervals for when each flower is in full bloom and query times for people arriving, return for each person…

Companies: Roblox

Array · Binary Search · Hash Table · Ordered Set

Partition Array Into Two Arrays to Minimize Sum Difference

Partition the 2n integers into two equal-sized groups (choose n elements for one group) to minimize the absolute difference of their sums — a constrained…

Companies: Salesforce

Array · Binary Search · Bit Manipulation · Bitmask

Reverse Pairs

Count the number of index pairs (i, j) with 0 ≤ i < j < n such that nums[i] > 2 * nums[j]; this is…

Companies: eBay

Array · Binary Indexed Tree · Binary Search · Divide and Conquer

Sell Diminishing-Valued Colored Balls

Given inventories where each sale of a color yields value equal to its current count and reduces that count by one, choose which balls to…

Companies: Goldman Sachs

Array · Binary Search · Greedy · Heap (Priority Queue)

Sqrt(x)

Compute the integer square root: for a non-negative integer x (0 ≤ x ≤ 2^31-1), return floor(sqrt(x)) without using built-in exponent functions — typically solved…

Companies: Google

Binary Search · Math · Newton's Method

Valid Triangle Number

Count the number of triplets (i, j, k) from nums that can form triangle side lengths — i.e., three values a ≤ b ≤ c…

Companies: Bloomberg

Array · Binary Search · Greedy · Sorting