Must Do Coding Questions for Companies like Amazon, Microsoft, Adobe, ... Last Updated : 23 Jul, 2025 Comments Improve Suggest changes Like Article Like Report The list in this article contains more than 200 questions according to the popularity in interview experiences. Arrays Subarray with given sum Count the triplets Kadane's Algorithm Missing number in array Merge two sorted arrays Rearrange array alternatively Number of pairs Inversion of Array Sort an array of 0s, 1s and 2s Equilibrium point Leaders in an array Minimum Platforms Reverse array in groups K’th smallest element Trapping Rain Water Pythagorean Triplet Chocolate Distribution Problem Stock buy and sell Element with left side smaller and right side greater Convert array into Zig-Zag fashion Last Index of 1 Spirally traversing a matrix Largest Number formed from an Array String Reverse words in a given string Permutations of a given string Longest Palindrome in a String Recursively remove all adjacent duplicates Check if string is rotated by two places Roman Number to Integer Anagram Remove Duplicates Form a Palindrome Longest Distinct Characters in the string Implement Atoi Implement strstr Longest Common Prefix Linked List Finding middle element in a linked list Reverse a linked list Rotate a Linked List Reverse a Linked List in groups of given size Intersection point in Y shaped linked lists Detect Loop in linked list Remove loop in Linked List n'th node from end of linked list Flattening a Linked List Merge two sorted linked lists Intersection point of two Linked Lists Pairwise swap of a linked list Add two numbers represented by linked lists Check if Linked List is Palindrome Implement Queue using Linked List Implement Stack using Linked List Given a linked list of 0s, 1s and 2s, sort it Delete without head pointer Stack and Queue Parenthesis Checker Next larger element Queue using two Stacks Stack using two queues Get minimum element from stack LRU Cache Circular tour First non-repeating character in a stream Rotten Oranges Maximum of all subarrays of size k Tree Print Left View of Binary Tree Check for BST Print Bottom View of Binary Tree Print a Binary Tree in Vertical Order Level order traversal in spiral form Connect Nodes at Same Level Lowest Common Ancestor in a BST Convert a given Binary Tree to Doubly Linked List Write Code to Determine if Two Trees are Identical or Not Given a binary tree, check whether it is a mirror of itself Height of Binary Tree Maximum Path Sum Diameter of a Binary Tree Number of leaf nodes Check if given Binary Tree is Height Balanced or Not Serialize and Deserialize a Binary Tree Heap Find median in a stream Heap Sort Operations on Binary Min Heap Rearrange characters Merge K sorted linked lists Kth largest element in a stream Recursion Flood fill Algorithm Number of paths Combination Sum - Part 2 Special Keyboard Josephus problem Hashing Relative Sorting Sorting Elements of an Array by Frequency Largest subarray with 0 sum Common elements Find all four sum numbers Swapping pairs make sum equal Count distinct elements in every window Array Pair Sum Divisibility Problem Longest consecutive subsequence Array Subset of another array Find all pairs with a given sum Find first repeated character Zero Sum Subarrays Minimum indexed character Check if two arrays are equal or not Uncommon characters Smallest window in a string containing all the characters of another string First element to occur k times Check if frequencies can be equal Graph Depth First Traversal Breadth First Traversal Detect cycle in undirected graph Detect cycle in a directed graph Topological sort Find the number of islands Implementing Dijkstra Minimum Swaps Strongly Connected Components Shortest Source to Destination Path Find whether path exist Minimum Cost Path Circle of Strings Floyd Warshall Alien Dictionary Snake and Ladder Problem Greedy Activity Selection N meetings in one room Coin Piles Maximize Toys Page Faults in LRU Largest number possible Minimize the heights Minimize the sum of product Huffman Decoding Minimum Spanning Tree Shop in Candy Store Geek collects the balls Dynamic Programming Minimum Operations Max length chain Minimum number of Coins Longest Common Substring Longest Increasing Subsequence Longest Common Subsequence 0 - 1 Knapsack Problem Maximum sum increasing subsequence Minimum number of jumps Edit Distance Coin Change Problem Subset Sum Problem Box Stacking Rod Cutting Path in Matrix Minimum sum partition Count number of ways to cover a distance Egg Dropping Puzzle Optimal Strategy for a Game Shortest Common Supersequence Divide and Conquer Find the element that appears once in sorted array Search in a Rotated Array Binary Search Sum of Middle Elements of two sorted arrays Quick Sort Merge Sort K-th element of two sorted Arrays Backtracking N-Queen Problem Solve the Sudoku Rat in a Maze Problem Word Boggle Generate IP Addresses Bit Magic Find first set bit Rightmost different bit Check whether K-th bit is set or not Toggle bits given range Set kth bit Power of 2 Bit Difference Rotate Bits Swap all odd and even bits Count total set bits Longest Consecutive 1's Sparse Number Alone in a couple Maximum subset XOR Some More Questions on Arrays Find Missing And Repeating Maximum Index Consecutive 1's not allowed Majority Element Two numbers with sum closest to zero Nuts and Bolts Problem Boolean Matrix Problem Smallest Positive missing number Jumping Caterpillars Some More Questions on Strings Most frequent word in an array of strings CamelCase Pattern Matching String Ignorance Smallest window in a string containing all the characters of another string Design a tiny URL or URL shortener Permutations of a given string Non Repeating Character Check if strings are rotations of each other or not Save Ironman Repeated Character Remove common characters and concatenate Geek and its Colored Strings Second most repeated string in a sequence Some more Questions on Trees Mirror Tree Longest consecutive sequence in Binary tree Bottom View of Binary Tree Lowest Common Ancestor in a Binary Tree Binary to DLL Important Links : Difficulty-wise ordered Coding questions for Interview and Competitive Programming Aptitude questions asked in round 1 : Placements Course designed for this purpose. MCQs asked from different computer science subjects : Subject-Wise Quizzes Interview theory and coding questions of all companies : Company wise all practice questions . Interview experiences of all companies : Interview corner. Preparing for Product-Based Companies ? Check Out Must Do Coding Questions for Product Based Companies If you are looking for shorter list, please refer Top 75 DSA QuestionsFor preparing for interviews with companies like Amazon or Microsoft, the GeeksforGeeks Online Practice Platform offers curated problem sets that mimic the challenges faced in these interviews. 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Comment More infoAdvertise with us Next Article Asymptotic Notations for Analysis of Algorithms K kartik Follow Improve Article Tags : DSA interview-preparation placement preparation GFG-Update GFG Sheets +1 More Similar Reads Basics & PrerequisitesTime and Space ComplexityMany times there are more than one ways to solve a problem with different algorithms and we need a way to compare multiple ways. Also, there are situations where we would like to know how much time and resources an algorithm might take when implemented. To measure performance of algorithms, we typic 13 min read Asymptotic Notations for Analysis of AlgorithmsWe have discussed Asymptotic Analysis, and Worst, Average, and Best Cases of Algorithms. The main idea of asymptotic analysis is to have a measure of the efficiency of algorithms that don't depend on machine-specific constants and don't require algorithms to be implemented and time taken by programs 8 min read Data StructuresArray Data Structure GuideIn 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. The following facts make string an interesting data structure.Small set of elements. Unlike normal array, strings typically have smaller set of items. For example, lowercase English alphabet has only 26 characters. ASCII has only 256 characters.Strings are immut 2 min read Hashing in Data StructureHashing is a technique used in data structures that efficiently stores and retrieves data in a way that allows for quick access. Hashing involves mapping data to a specific index in a hash table (an array of items) using a hash function. It enables fast retrieval of information based on its key. The 2 min read Linked List Data StructureA linked list is a fundamental data structure in computer science. It mainly allows efficient insertion and deletion operations compared to arrays. Like arrays, it is also used to implement other data structures like stack, queue and deque. 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 Corner: All Resources To Crack Any Tech InterviewThis 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 GfG160 - 160 Days of Problem SolvingAre 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