Data Structures and Algorithms
Understand Solutions Easily with Visualizations

Overview of Techniques14

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1. 1Overview of DSA Problem Solving Techniques
2. 2Brute Force Technique in DSA
3. 3Greedy Algorithm Technique in DSA
4. 4Divide and Conquer Technique in DSA
5. 5Dynamic Programming Technique in DSA
6. 6Backtracking Technique in DSA
7. 7Recursion Technique in DSA
8. 8Sliding Window Technique in DSA
9. 9Two Pointers Technique
10. 10Binary Search Technique
11. 11Tree / Graph Traversal Technique in DSA
12. 12Bit Manipulation Technique in DSA
13. 13Hashing Technique
14. 14Heaps Technique in DSA

Sorting6

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ComparisonDivide and ConquerGreedy TechniqueHeapifyIn-PlaceIterative AlgorithmMax HeapRecursive AlgorithmSortingStable SortSHOW ALL

1. 1Bubble Sort
2. 2Selection Sort
3. 3Insertion Sort
4. 4Merge Sort
5. 5Quick Sort
6. 6Heap Sort

Arrays32

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BinaryBoyer-Moore Voting AlgorithmCheckComparisonCountingDivide and ConquerDuplicatesDutch National FlagDynamic ProgrammingFormulaGreedyHash MapHashSetHashingIn-PlaceIn-place OperationKadane's AlgorithmKadane’s AlgorithmKthLinear SearchMaximumMinimumPermutationQuickselectRandomizedRearrangementReversalRotationSearchSelectionSequence ProblemsSet OperationsSingle PassSliding WindowSortSortingSubarray ProblemsSum ProblemsSwapTwo PointersUnionZeroesSHOW ALL

1. 1Find Maximum and Minimum in Array using Loop
2. 2Find Second Largest in Array
3. 3Find Second Smallest in Array
4. 4Reverse Array using Two Pointers
5. 5Check if Array is Sorted
6. 6Remove Duplicates from Sorted Array
7. 7Left Rotate an Array by One Place
8. 8Left Rotate an Array by K Places
9. 9Move Zeroes in Array to End
10. 10Linear Search in Array
11. 11Union of Two Arrays
12. 12Find Missing Number in Array
13. 13Max Consecutive Ones in Array
14. 14Find Kth Smallest Element
15. 15Longest Subarray with Given Sum (Positives)
16. 16Longest Subarray with Given Sum (Positives and Negatives)
17. 17Find Majority Element in Array (more than n/2 times)
18. 18Find Majority Element in Array (more than n/3 times)
19. 19Maximum Subarray Sum using Kadane's Algorithm
20. 20Print Subarray with Maximum Sum
21. 21Stock Buy and Sell
22. 22Rearrange Array Alternating Positive and Negative Elements
23. 23Next Permutation of Array
24. 24Leaders in an Array
25. 25Longest Consecutive Sequence in Array
26. 26Count Subarrays with Given Sum
27. 27Sort an Array of 0s, 1s, and 2s
28. 28Two Sum Problem
29. 29Three Sum Problem
30. 304 Sum Problem
31. 31Find Length of Largest Subarray with 0 Sum
32. 32Find Maximum Product Subarray

Arrays - Binary Search28

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Bit ManipulationBook AllocationCountingDivide and ConquerDuplicatesGreedyLower/Upper BoundsMathMedianMissing NumbersOptimizationPartitionPartitioningPeakPlacementRotated ArrayRotationSearchSquare RootTwo PointersSHOW ALL

1. 1Binary Search in Array using Iteration
2. 2Find Lower Bound in Sorted Array
3. 3Find Upper Bound in Sorted Array
4. 4Search Insert Position in Sorted Array (Lower Bound Approach)
5. 5Floor and Ceil in Sorted Array
6. 6First Occurrence in a Sorted Array
7. 7Last Occurrence in a Sorted Array
8. 8Count Occurrences in Sorted Array
9. 9Search Element in a Rotated Sorted Array
10. 10Search in Rotated Sorted Array with Duplicates
11. 11Minimum in Rotated Sorted Array
12. 12Find Rotation Count in Sorted Array
13. 13Search Single Element in Sorted Array
14. 14Find Peak Element in Array
15. 15Square Root using Binary Search
16. 16Nth Root of a Number using Binary Search
17. 17Koko Eating Bananas
18. 18Minimum Days to Make M Bouquets
19. 19Find the Smallest Divisor Given a Threshold
20. 20Capacity to Ship Packages within D Days
21. 21Kth Missing Positive Number
22. 22Aggressive Cows Problem
23. 23Allocate Minimum Number of Pages
24. 24Split Array - Minimize Largest Sum
25. 25Painter's Partition Problem
26. 26Minimize Maximum Distance Between Gas Stations
27. 27Median of Two Sorted Arrays of Different Sizes
28. 28K-th Element of Two Sorted Arrays

Strings18

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2D DPAnagram CheckDepthDynamic ProgrammingEdge CasesFrequency CountGreedyHash MapHashMapHashingHeapMathematicsOne-to-One MappingPalindromeParenthesesParsingPrefixRoman NumeralsRotationSearchSliding WindowSortingSplit and JoinStackStringString ManipulationString MappingString MatchingString ParsingString TraversalStringsSubstringsTwo PointersVertical ScanningWord ReversalSHOW ALL

1. 1Reverse Words in a String
2. 2Find the Largest Odd Number in a Numeric String
3. 3Find Longest Common Prefix in Array of Strings
4. 4Check If Two Strings Are Isomorphic - Optimal HashMap Solution
5. 5Check String Rotation using Concatenation - Optimal Approach
6. 6Check if Two Strings Are Anagrams - Optimal Approach
7. 7Sort Characters by Frequency - Optimal HashMap and Heap Approach
8. 8Find Longest Palindromic Substring - Dynamic Programming Approach
9. 9Find Longest Palindromic Substring Without Dynamic Programming
10. 10Remove Outermost Parentheses in String
11. 11Find Maximum Nesting Depth of Parentheses - Optimal Stack-Free Solution
12. 12Convert Roman Numerals to Integer - Efficient Approach
13. 13Convert Integer to Roman Numeral - Step-by-Step for Beginners
14. 14Implement Atoi - Convert String to Integer in Java
15. 15Count Number of Substrings in a String - Explanation with Formula
16. 16Edit Distance Problem
17. 17Calculate Sum of Beauty of All Substrings - Optimal Approach
18. 18Reverse Each Word in a String - Optimal Approach

Matrix3

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In-PlaceRotationTransformationsTraversalZeroesSHOW ALL

1. 1Set Matrix Zeroes
2. 2Rotate Matrix by 90 Degrees Clockwise
3. 3Print Matrix in Spiral Manner

Matrix - Binary Search4

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Binary MatrixBinary SearchMatrixMedianSearchSHOW ALL

1. 1Row with Maximum Number of 1's
2. 2Search in a Sorted 2D Matrix
3. 3Search in Row and Column-wise Sorted Matrix
4. 4Matrix Median

Binary Trees36

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Binary TreesRecursionTree TraversalSHOW ALL

1. 1Preorder Traversal of a Binary Tree using Recursion
2. 2Preorder Traversal of a Binary Tree using Iteration
3. 3Inorder Traversal of a Binary Tree using Recursion
4. 4Inorder Traversal of a Binary Tree using Iteration
5. 5Postorder Traversal of a Binary Tree Using Recursion
6. 6Postorder Traversal of a Binary Tree using Iteration
7. 7Level Order Traversal of a Binary Tree using Recursion
8. 8Level Order Traversal of a Binary Tree using Iteration
9. 9Reverse Level Order Traversal of a Binary Tree using Iteration
10. 10Reverse Level Order Traversal of a Binary Tree using Recursion
11. 11Find Height of a Binary Tree
12. 12Find Diameter of a Binary Tree
13. 13Find Mirror of a Binary Tree
14. 14Left View of a Binary Tree
15. 15Right View of a Binary Tree
16. 16Top View of a Binary Tree
17. 17Bottom View of a Binary Tree
18. 18Zigzag Traversal of a Binary Tree
19. 19Check if a Binary Tree is Balanced
20. 20Diagonal Traversal of a Binary Tree
21. 21Boundary Traversal of a Binary Tree
22. 22Construct a Binary Tree from a String with Bracket Representation
23. 23Convert a Binary Tree into a Doubly Linked List
24. 24Convert a Binary Tree into a Sum Tree
25. 25Find Minimum Swaps Required to Convert a Binary Tree into a BST
26. 26Check if a Binary Tree is a Sum Tree
27. 27Check if All Leaf Nodes are at the Same Level in a Binary Tree
28. 28Lowest Common Ancestor (LCA) in a Binary Tree
29. 29Solve the Tree Isomorphism Problem
30. 30Check if a Binary Tree Contains Duplicate Subtrees of Size 2 or More
31. 31Check if Two Binary Trees are Mirror Images
32. 32Calculate the Sum of Nodes on the Longest Path from Root to Leaf in a Binary Tree
33. 33Print All Paths in a Binary Tree with a Given Sum
34. 34Find the Distance Between Two Nodes in a Binary Tree
35. 35Find the kth Ancestor of a Node in a Binary Tree
36. 36Find All Duplicate Subtrees in a Binary Tree

Binary Search Trees14

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Binary Search TreesSHOW ALL

1. 1Find a Value in a Binary Search Tree
2. 2Delete a Node in a Binary Search Tree
3. 3Find the Minimum Value in a Binary Search Tree
4. 4Find the Maximum Value in a Binary Search Tree
5. 5Find the Inorder Successor in a Binary Search Tree
6. 6Find the Inorder Predecessor in a Binary Search Tree
7. 7Check if a Binary Tree is a Binary Search Tree
8. 8Find the Lowest Common Ancestor of Two Nodes in a Binary Search Tree
9. 9Convert a Binary Tree into a Binary Search Tree
10. 10Balance a Binary Search Tree
11. 11Merge Two Binary Search Trees
12. 12Find the kth Largest Element in a Binary Search Tree
13. 13Find the kth Smallest Element in a Binary Search Tree
14. 14Flatten a Binary Search Tree into a Sorted List

Graphs46

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2D GridAll Pairs Shortest PathArticulation PointBFSBacktrackingBellman-FordBinary MazeBipartite GraphBreadth First SearchBridgesConnected ComponentsConnectivityCritical ConnectionsCycle DetectionDAGDFSDSUDepth First SearchDijkstraDirected Acyclic GraphDirected GraphDisjoint SetDisjoint Set UnionDynamic ConnectivityDynamic ProgrammingEdge RelaxationEffort PathEmail MergeFlood FillFloyd WarshallFloyd-WarshallGraphGraph AlgorithmsGraph BFSGraph TheoryGraph TraversalGraphsGreedyGreedy AlgorithmsGridGrid TraversalHeapImage ProcessingKahn's AlgorithmKahn’s AlgorithmKosarajuKruskalKruskal's AlgorithmMSTMatrixMinimum Spanning TreeNegative WeightsPath CompressionPrim's AlgorithmPriority QueueQueueRecursionRotten OrangesSafe StatesSetShape EncodingShortest PathSimulationSpanning TreeStrongly Connected ComponentsTarjanThreshold DistanceTopological SortTranspose GraphUndirected GraphUnion FindUnion by RankUnion-FindUnweighted GraphWord LadderSHOW ALL

1. 1Breadth-First Search in Graphs
2. 2Depth-First Search in Graphs
3. 3Number of Provinces in an Undirected Graph
4. 4Connected Components in a Matrix
5. 5Rotten Oranges Problem - BFS in Matrix
6. 6Flood Fill Algorithm - Graph Based
7. 7Detect Cycle in an Undirected Graph using DFS
8. 8Detect Cycle in an Undirected Graph using BFS
9. 9Distance of Nearest Cell Having 1 - Grid BFS
10. 10Surrounded Regions in Matrix using Graph Traversal
11. 11Number of Enclaves in Grid
12. 12Word Ladder - Shortest Transformation using Graph
13. 13Word Ladder II - All Shortest Transformation Sequences
14. 14Number of Distinct Islands using DFS
15. 15Check if a Graph is Bipartite using DFS
16. 16Topological Sort Using DFS
17. 17Topological Sort using Kahn's Algorithm
18. 18Cycle Detection in Directed Graph using BFS
19. 19Course Schedule - Task Ordering with Prerequisites
20. 20Course Schedule 2 - Task Ordering Using Topological Sort
21. 21Find Eventual Safe States in a Directed Graph
22. 22Alien Dictionary Character Order
23. 23Shortest Path in Undirected Graph with Unit Distance
24. 24Shortest Path in DAG using Topological Sort
25. 25Dijkstra's Algorithm Using Set - Shortest Path in Graph
26. 26Dijkstra’s Algorithm Using Priority Queue
27. 27Shortest Distance in a Binary Maze using BFS
28. 28Path With Minimum Effort in Grid using Graphs
29. 29Cheapest Flights Within K Stops - Graph Problem
30. 30Number of Ways to Reach Destination in Shortest Time - Graph Problem
31. 31Minimum Multiplications to Reach End - Graph BFS
32. 32Bellman-Ford Algorithm for Shortest Paths
33. 33Floyd Warshall Algorithm for All-Pairs Shortest Path
34. 34Find the City With the Fewest Reachable Neighbours
35. 35Minimum Spanning Tree in Graphs
36. 36Prim's Algorithm for Minimum Spanning Tree
37. 37Disjoint Set (Union-Find) with Union by Rank and Path Compression
38. 38Kruskal's Algorithm - Minimum Spanning Tree
39. 39Minimum Operations to Make Network Connected
40. 40Most Stones Removed with Same Row or Column
41. 41Accounts Merge Problem using Disjoint Set Union
42. 42Number of Islands II - Online Queries using DSU
43. 43Making a Large Island Using DSU
44. 44Bridges in Graph using Tarjan's Algorithm
45. 45Articulation Points in Graphs
46. 46Strongly Connected Components using Kosaraju's Algorithm

Tries4

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Basic OperationSHOW ALL

1. 1Search Word in Trie
2. 2Insert Word in Trie
3. 3Prefix Search in Trie
4. 4Delete Word from Trie