Top 50 Algorithms Interview Questions

Use a two-pointer string scan to determine whether a string reads the same forward and backward.

RecursionStringsData StructuresDsv Air & SeaLucid MotorsAfterquery

Detect whether a linked list contains a cycle using Floyd's tortoise-and-hare algorithm in O(n) time and O(1) space.

Linked ListsData Structurescycle detectionTTripJackLumenaltaJ.P. Morgan

Reverse a singly linked list in place by rewiring next pointers in one pass.

Linked ListsAlgorithmsGeneral AtomicsKKotakKotak Mahindra Bank

Optimize repeated range-sum computations with prefix sums instead of rescanning application workload data.

Hash TablesArraysSortingUniversity of FloridaCybertrend EngineeringDiamond Foundry

Implement a modular top-k frequency algorithm that scales with input size and preserves deterministic tie ordering.

clean codecode qualityDynamic ProgrammingTotalEnergiesJohnson & JohnsonL3Harris Technologies

Compute cosine similarity for equal-length high-dimensional vectors using dot products and Euclidean norms.

function implementationArraysArray ManipulationCommonwealth Bank of AustraliaLLogicFFever