Top 10 Algorithms in Interview Questions Last Updated : 21 Aug, 2025 Comments Improve Suggest changes Like Article Like Report Getting ready for a tech job interview? Algorithms are really important! Companies often ask questions that require problem-solving skills. In this article, we'll look at the top 10 algorithms commonly used in interviews. Each algorithm is like a powerful tool in your problem-solving toolbox. Knowing them well can really help you handle different technical challenges during interviews. Let's break down these important algorithms to make your interview preparation more effective. If you're getting ready for a coding interview, it's essential to go through these problems.1. Array AlgorithmMaximum Subarray SumFind the Missing NumberTrapping Rain WaterMaximum Product SubarrayFind the equilibrium index of an arrayLeaders in an arrayMinimum Platforms Required for a Railway/Bus StationRotate an array to the right by k stepsKth smallest/largest element in an arrayMaximum Length Bitonic SubarrayFor more, please refer: Array Data Structure Guide2. String AlgorithmLongest Palindromic SubstringString Matching with WildcardEdit DistanceLongest Repeating SubsequenceCount all distinct substrings of a given stringReverse words in a given stringCheck if a string is a rotated palindromeKMP Algorithm for Pattern SearchingMinimum characters to be added at front to make string palindromeFor more, please refer: String Data Structure3. Sorting AlgorithmQuickSortMergeSortHeapSortCounting SortRadix SortBubble SortSelection SortInsertion SortShell SortBucket SortFor more, please refer: Sorting Algorithms4. Searching AlgorithmLinear SearchBinary SearchTernary SearchDepth-First Search (DFS)Breadth-First Search (BFS)Fibonacci SearchFor more, please refer: Searching Algorithms5. Recursion/Backtracking AlgorithmN-Queens ProblemSudoku SolverRat in a MazeWord Break Problem using BacktrackingSubset Sum ProblemPermutations of a given stringCombination SumGenerate all possible valid IP addresses from given stringRat in a Maze with multiple steps or jump allowedFor more, please refer: Recursion/Backtracking Algorithm6. Greedy AlgorithmFractional KnapsackHuffman CodingJob Sequencing with DeadlinesActivity Selection ProblemGreedy Algorithm to find Minimum number of CoinsMinimum Number of Platforms Required for a Railway/Bus StationMaximum Length Chain of PairsMinimize Cash Flow among a given set of friends who have borrowed money from each otherConnect n Ropes with Minimum CostPrim's Minimum Spanning Tree (MST)For more, please refer: Greedy Algorithms7. Tree AlgorithmLowest Common Ancestor (LCA)Diameter of Binary TreeBinary Tree Level Order TraversalSerialize and Deserialize a Binary TreeCheck if a Binary Tree is BSTInorder Traversal without RecursionConvert Binary Tree to Doubly Linked ListCheck if Two Trees are IdenticalMaximum Width of a Binary TreeMirror of a Binary TreeFor more, please refer: Tree Data Structure8. Dynamic Programming AlgorithmLongest Common Subsequence0/1 KnapsackMatrix Chain MultiplicationLongest Increasing SubsequenceMaximum Sum Increasing SubsequenceCoin Change ProblemLongest Palindromic SubsequenceEdit DistanceLargest Sum Contiguous SubarrayLongest Common SubstringFor more, please refer: Dynamic Programming9. Graph AlgorithmDijkstra's AlgorithmKruskal's AlgorithmTopological SortingBellman-Ford AlgorithmFloyd Warshall AlgorithmPrim's AlgorithmDepth-First Traversal of a GraphBreadth-First Traversal of a GraphDetect Cycle in a Directed GraphArticulation Points (or Cut Vertices) in a GraphFor more, please refer: Graph Algorithms10. Bit Manipulation AlgorithmFind the Only Non-Repeating ElementCount Total Set BitsMaximum XOR of Two Numbers in an ArrayFind the two non-repeating elements in an array of repeating elementsCheck if a number is sparse or notCount total set bits in all numbers from 1 to nMaximum subarray XOR in a given arraySum of XOR of all subarraysFind the element that appears once in an array where every other element appears twiceProgram to find whether a no is power of twoFor more, please refer: Bitwise AlgorithmsRelated Articles:Top 50 Array Coding Problems for InterviewsTop 50 String Coding Problems for InterviewsTop 50 Problems on Heap Data for InterviewsTop 50 Tree Coding Problems for InterviewsTop 50 Dynamic Programming Coding ProblemsTop 50 Graph Coding Problems for InterviewsTop 50 Problems on Stack Problems for InterviewsTop 50 Problems on Linked List Problems for InterviewsTop 50 Problems on Matrix/Grid Problems for InterviewsMust Do Coding Questions for Product Based CompaniesMust Do Coding Questions for Companies like Amazon Comment More infoAdvertise with us K kartik Follow Improve Article Tags : DSA Interview Tips interview-preparation placement preparation BFS DFS Topological Sorting Interview-Questions +4 More Practice Tags : BFSDFS Similar Reads Basics & PrerequisitesLogic Building ProblemsLogic building is about creating clear, step-by-step methods to solve problems using simple rules and principles. It’s the heart of coding, enabling programmers to think, reason, and arrive at smart solutions just like we do.Here are some tips for improving your programming logic: Understand the pro 2 min read Analysis of AlgorithmsAnalysis of Algorithms is a fundamental aspect of computer science that involves evaluating performance of algorithms and programs. Efficiency is measured in terms of time and space.BasicsWhy is Analysis Important?Order of GrowthAsymptotic Analysis Worst, Average and Best Cases Asymptotic NotationsB 1 min read Data StructuresArray Data StructureIn this article, we introduce array, implementation in different popular languages, its basic operations and commonly seen problems / interview questions. An array stores items (in case of C/C++ and Java Primitive Arrays) or their references (in case of Python, JS, Java Non-Primitive) at contiguous 3 min read String in Data StructureA string is a sequence of characters. 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Here’s the comparison of Linked List vs Arrays Linked List: 2 min read Stack Data StructureA Stack is a linear data structure that follows a particular order in which the operations are performed. The order may be LIFO(Last In First Out) or FILO(First In Last Out). LIFO implies that the element that is inserted last, comes out first and FILO implies that the element that is inserted first 2 min read Queue Data StructureA Queue Data Structure is a fundamental concept in computer science used for storing and managing data in a specific order. It follows the principle of "First in, First out" (FIFO), where the first element added to the queue is the first one to be removed. It is used as a buffer in computer systems 2 min read Tree Data StructureTree Data Structure is a non-linear data structure in which a collection of elements known as nodes are connected to each other via edges such that there exists exactly one path between any two nodes. Types of TreeBinary Tree : Every node has at most two childrenTernary Tree : Every node has at most 4 min read Graph Data StructureGraph Data Structure is a collection of nodes connected by edges. It's used to represent relationships between different entities. If you are looking for topic-wise list of problems on different topics like DFS, BFS, Topological Sort, Shortest Path, etc., please refer to Graph Algorithms. Basics of 3 min read Trie Data StructureThe Trie data structure is a tree-like structure used for storing a dynamic set of strings. It allows for efficient retrieval and storage of keys, making it highly effective in handling large datasets. Trie supports operations such as insertion, search, deletion of keys, and prefix searches. In this 15+ min read AlgorithmsSearching AlgorithmsSearching algorithms are essential tools in computer science used to locate specific items within a collection of data. In this tutorial, we are mainly going to focus upon searching in an array. When we search an item in an array, there are two most common algorithms used based on the type of input 2 min read Sorting AlgorithmsA Sorting Algorithm is used to rearrange a given array or list of elements in an order. For example, a given array [10, 20, 5, 2] becomes [2, 5, 10, 20] after sorting in increasing order and becomes [20, 10, 5, 2] after sorting in decreasing order. There exist different sorting algorithms for differ 3 min read Introduction to RecursionThe process in which a function calls itself directly or indirectly is called recursion and the corresponding function is called a recursive function. A recursive algorithm takes one step toward solution and then recursively call itself to further move. The algorithm stops once we reach the solution 14 min read Greedy AlgorithmsGreedy algorithms are a class of algorithms that make locally optimal choices at each step with the hope of finding a global optimum solution. At every step of the algorithm, we make a choice that looks the best at the moment. To make the choice, we sometimes sort the array so that we can always get 3 min read Graph AlgorithmsGraph is a non-linear data structure like tree data structure. The limitation of tree is, it can only represent hierarchical data. For situations where nodes or vertices are randomly connected with each other other, we use Graph. Example situations where we use graph data structure are, a social net 3 min read Dynamic Programming or DPDynamic Programming is an algorithmic technique with the following properties.It is mainly an optimization over plain recursion. Wherever we see a recursive solution that has repeated calls for the same inputs, we can optimize it using Dynamic Programming. The idea is to simply store the results of 3 min read Bitwise AlgorithmsBitwise algorithms in Data Structures and Algorithms (DSA) involve manipulating individual bits of binary representations of numbers to perform operations efficiently. These algorithms utilize bitwise operators like AND, OR, XOR, NOT, Left Shift, and Right Shift.BasicsIntroduction to Bitwise Algorit 4 min read AdvancedSegment TreeSegment Tree is a data structure that allows efficient querying and updating of intervals or segments of an array. It is particularly useful for problems involving range queries, such as finding the sum, minimum, maximum, or any other operation over a specific range of elements in an array. The tree 3 min read Pattern SearchingPattern searching algorithms are essential tools in computer science and data processing. These algorithms are designed to efficiently find a particular pattern within a larger set of data. Patten SearchingImportant Pattern Searching Algorithms:Naive String Matching : A Simple Algorithm that works i 2 min read GeometryGeometry is a branch of mathematics that studies the properties, measurements, and relationships of points, lines, angles, surfaces, and solids. From basic lines and angles to complex structures, it helps us understand the world around us.Geometry for Students and BeginnersThis section covers key br 2 min read Interview PreparationInterview CornerThis article serves as your one-stop guide to interview preparation, designed to help you succeed across different experience levels and company expectations. Here is what you should expect in a Tech Interview, please remember the following points:Tech Interview Preparation does not have any fixed s 3 min read GfG160Are you preparing for technical interviews and would like to be well-structured to improve your problem-solving skills? Well, we have good news for you! GeeksforGeeks proudly presents GfG160, a 160-day coding challenge starting on 15th November 2024. In this event, we will provide daily coding probl 3 min read Practice ProblemGeeksforGeeks Practice - Leading Online Coding PlatformGeeksforGeeks Practice is an online coding platform designed to help developers and students practice coding online and sharpen their programming skills with the following features. GfG 160: This consists of most popular interview problems organized topic wise and difficulty with with well written e 6 min read Problem of The Day - Develop the Habit of CodingDo you find it difficult to develop a habit of Coding? If yes, then we have a most effective solution for you - all you geeks need to do is solve one programming problem each day without any break, and BOOM, the results will surprise you! Let us tell you how:Suppose you commit to improve yourself an 5 min read Like