Interview questions

Fraction to Recurring Decimal

Convert a fraction to its decimal string form, enclosing any repeating fractional cycle in parentheses. The core challenge is simulating long division while handling sign…

Companies: Goldman Sachs, Meta

Hash Table · Math · String

Last reported Sep 2026

K Closest Points to Origin

Given N points on the plane and an integer k, return the k points with the smallest Euclidean distance to the origin (order doesn't matter)…

Companies: Airbnb, Amazon, Asana, Meta

Array · Divide and Conquer · Geometry · Heap (Priority Queue)

Last reported Aug 2026

Maximum Xor Product

Choose an integer x in [0, 2^n) to maximize (a XOR x) * (b XOR x) (answer mod 1e9+7); the core challenge is picking x’s…

Companies: Atlassian, Cisco, Zomato

Bit Manipulation · Greedy · Math

Last reported Jul 2026

Maximum Product of Three Numbers

Given an integer array, return the maximum product obtainable by multiplying any three numbers. Consider both the three largest values and the combination of the…

Companies: Salesforce

Array · Math · Sorting

Last reported Jun 2026

Random Pick with Weight

Given an array of positive weights, implement pickIndex() to return index i with probability w[i]/sum(w); the typical approach preprocessing prefix sums and using a random…

Companies: Amazon, Apple, Goldman Sachs, Meta +4

Array · Binary Search · Math · Prefix Sum

Last reported Jun 2026

Rotate Array

Rotate an integer array to the right by k steps (k may exceed the array length), effectively moving each element to index (i+k) mod n…

Companies: Apple, Microsoft, Nutanix, TikTok

Array · Math · Two Pointers

Last reported Jun 2026

Reverse Integer

Reverse the digits of a signed 32-bit integer, preserving the sign, and return the reversed number or 0 if reversing would overflow the 32-bit signed…

Companies: Bloomberg, eBay, Google, Meta +2

Math

Last reported May 2026

Happy Number

Determine whether iterating n -> sum of the squares of its digits eventually reaches 1 or falls into a repeating cycle; the core task is…

Companies: Snowflake

Floyd's Cycle Finding Algorithm · Hash Table · Math · Two Pointers

Last reported May 2026

Basic Calculator III

Evaluate a string arithmetic expression containing integers, +, -, *, /, parentheses and unary signs, respecting operator precedence and parentheses. The challenge is to parse…

Companies: Google, Intuit, Meta

Math · Recursion · Stack · String

Last reported May 2026

Integer to English Words

Convert a non-negative integer to its English words representation. The core challenge is chunking the number into three-digit groups (ones, thousands, millions, billions)…

Companies: Amazon, Microsoft

Math · Recursion · String

Last reported Mar 2026

Shuffle an Array

Design a class that stores an integer array and supports reset (returning the original configuration) and shuffle (returning a uniformly random permutation so that all…

Companies: Microsoft, Uber

Array · Design · Math · Randomized

Last reported Feb 2026

Find the Closest Palindrome

Given a numeric string n (up to 18 digits), find the closest integer palindrome different from n (ties broken by smaller value). The typical approach…

Companies: Meta, Uber

Math · String

Last reported Jan 2026

Expression Add Operators

Given a digit string and a target value, insert the binary operators +, -, and * between digits (without creating operands with leading zeros) to…

Companies: LinkedIn, Meta, Pinterest

Backtracking · Math · String

Last reported Jan 2026

Add Two Numbers

Companies: Amazon, Bloomberg, Google, Meta +2

Linked List · Math · Recursion

Last reported Oct 2025

Consecutive Numbers Sum

Count how many ways a given n (1 ≤ n ≤ 10^9) can be written as a sum of consecutive positive integers. The core challenge…

Companies: Meta, Microsoft

Enumeration · Math

Last reported Oct 2025

Angle Between Hands of a Clock

Compute the positions of the clock's hour and minute hands (noting the hour hand moves continuously with minutes) and return the smaller angular difference between…

Companies: Microsoft, Salesforce, Zoho

Math

Last reported Sep 2025

Multiply Strings

Multiply two non-negative integer strings without converting them to numeric types or using BigInteger: compute the product by simulating grade-school digit-by-digit…

Companies: Meta, Microsoft, Pinterest

Math · Simulation · String

Last reported Sep 2025

Palindrome Number

Determine whether an integer's digit sequence reads the same forwards and backwards (return false for negative numbers); the follow-up asks to do this without converting…

Companies: Amazon, Bloomberg, Google, Meta +1

Math

Last reported May 2025

Add Two Numbers II

Companies: Meta, Pinterest

Linked List · Math · Stack

Last reported May 2025

Rotate Image

Given an n×n matrix, rotate it 90° clockwise in-place (no extra matrix allowed), i.e., rearrange the elements so each row becomes the corresponding column after…

Companies: Bloomberg, ByteDance, Meta, NVIDIA

Array · Math · Matrix

Last reported Feb 2025

Max Points on a Line

Given up to 300 unique 2D points, return the maximum number that lie on the same straight line. The core challenge is grouping points by…

Companies: Google, LinkedIn

Array · Euclidean Algorithm · Geometry · Greatest Common Divisor

Last reported Jan 2025

Evaluate Reverse Polish Notation

Evaluate the integer value of an expression given in Reverse Polish Notation, where tokens are integers or the operators +, -, *, / and all…

Companies: Citadel, Google

Array · Math · Stack

Last reported Nov 2024