500+ Data Structures and Algorithms practice problems

Array:

  1. Find pair with given sum in the array
  2. Check if subarray with 0 sum is exists or not
  3. Print all sub-arrays with 0 sum
  4. Sort binary array in linear time
  5. Find a duplicate element in a limited range array
  6. Find largest sub-array formed by consecutive integers
  7. Find maximum length sub-array having given sum
  8. Find maximum length sub-array having equal number of 0’s and 1’s
  9. Sort an array containing 0’s, 1’s and 2’s (Dutch national flag problem)
  10. Inplace merge two sorted arrays
  11. Merge two arrays by satisfying given constraints
  12. Find index of 0 to replaced to get maximum length sequence of continuous ones
  13. Find maximum product of two integers in an array
  14. Shuffle a given array of elements (Fisher–Yates shuffle)
  15. Rearrange the array with alternate high and low elements
  16. Find equilibrium index of an array
  17. Find majority element in an array (Boyer–Moore majority vote algorithm)
  18. Move all zeros present in the array to the end
  19. Replace each element of array with product of every other element without using / operator
  20. Find Longest Bitonic Subarray in an array
  21. Find maximum difference between two elements in the array by satisfying given constraints
  22. Maximum subarray problem (Kadane’s algorithm)
  23. Print continuous subarray with maximum sum
  24. Maximum Sum Circular Subarray
  25. Find all distinct combinations of given length
  26. Find all distinct combinations of given length with repetition allowed
  27. Find maximum sequence of continuous 1’s formed by replacing at-most k zeroes by ones
  28. Find minimum sum subarray of given size k
  29. Find subarray having given sum in given array of integers
  30. Find the length of smallest subarray whose sum of elements is greater than the given number
  31. Find largest number possible from set of given numbers
  32. Find the smallest window in array sorting which will make the entire array sorted
  33. Find maximum sum path involving elements of given arrays
  34. Maximum profit earned by buying and selling shares any number of times
  35. Trapping Rain Water within given set of bars
  36. Longest Increasing Subsequence
  37. Longest Decreasing Subsequence Problem
  38. Find maximum product subarray in a given array
  39. Find maximum sum of subsequence with no adjacent elements
  40. Find minimum platforms needed in the station so to avoid any delay in arrival of any train
  41. Decode the array constructed from another array
  42. Sort an array using one swap
  43. Find Triplet with given sum in an array
  44. Length of longest continuous sequence with same sum in given binary arrays
  45. Rearrange array such that A[A[i]] is set to i for every element A[i]
  46. Reverse every consecutive m elements of the given subarray
  47. Maximum Product Subset Problem
  48. Find pairs with given difference k in the array
  49. Find pairs with given difference k in the array | Constant space solution
  50. 4 sum problem | Quadruplets with given sum
  51. Print all quadruplets with given sum | 4-sum problem extended
  52. Find odd occurring element in an array in single traversal
  53. Find two odd occurring element in an array without using any extra space
  54. Quickselect Algorithm
  55. Print all Triplets that forms Arithmetic Progression
  56. Print all triplets that forms Geometric Progression
  57. Print all combination of numbers from 1 to n having sum n
  58. Replace each element of the array by its corresponding rank in the array
  59. Print all Triplets in an array with sum less than or equal to given number
  60. Group elements of an array based on their first occurrence
  61. Find minimum difference between index of two given elements present in the array
  62. Find maximum absolute difference between sum of two non-overlapping sub-arrays
  63. Find all Symmetric Pairs in an Array of Pairs
  64. Partition an array into two sub-arrays with the same sum
  65. Find count of distinct elements in every sub-array of size k
  66. Find two numbers with maximum sum formed by array digits
  67. Print all sub-arrays of an array having distinct elements
  68. Find a Triplet having Maximum Product in an Array
  69. Find ways to calculate a target from elements of specified array
  70. Find Minimum Index of Repeating Element in an Array
  71. Generate Random Input from an Array according to given Probabilities
  72. Find pair in an array having minimum absolute sum
  73. Find Index of Maximum Occurring Element with Equal Probability
  74. Check if an Array is Formed by Consecutive Integers
  75. Find two non-overlapping pairs having same sum in an array
  76. Find Minimum Product among all Combinations of Triplets in an Array
  77. Replace every element of an array with the least greater element on its right
  78. Find all odd occurring elements in an array having limited range of elements
  79. Add elements of two arrays into a new array
  80. Count the distinct absolute values in the sorted array
  81. Print all combinations of positive integers in increasing order that sum to a given number
  82. Find all distinct combinations of given length — Part 2
  83. Find subarrays with given sum in an array
  84. Find the surpasser count for each element of an array
  85. Find maximum length sequence of continuous ones (Using Sliding Window)
  86. Find maximum length sequence of continuous ones
  87. Merging Overlapping Intervals
  88. Activity Selection Problem
  89. Job Sequencing Problem with Deadlines
  90. Introduction to Priority Queues using Binary Heaps
  91. Min Heap and Max Heap Implementation in C++
  92. Min Heap and Max Heap Implementation in Java
  93. Heap Sort (Out-of-place and In-place implementation in C++ and C)
  94. Check if given array represents min heap or not
  95. Convert Max Heap to Min Heap in linear time
  96. Find K’th largest element in an array
  97. Sort a K-Sorted Array
  98. Merge M sorted lists of variable length
  99. Find K’th smallest element in an array
  100. Find smallest range with at-least one element from each of the given lists
  101. Merge M sorted lists each containing N elements
  102. Insertion sort | Iterative & Recursive
  103. Selection sort | Iterative & Recursive
  104. Bubble sort | Iterative & Recursive
  105. Merge Sort
  106. Quicksort
  107. Iterative Implementation of Quicksort
  108. Hybrid QuickSort
  109. Quicksort using Dutch National Flag Algorithm
  110. Quick Sort using Hoare’s Partitioning scheme
  111. External merge sort
  112. Custom Sort | Sort elements by their frequency and Index
  113. Custom Sort | Sort elements of the array by order of elements defined by the second array
  114. Inversion Count of an array
  115. Segregate positive and negative integers in linear time
  116. Binary Search
  117. Ternary Search vs Binary search
  118. Interpolation search
  119. Exponential search
  120. Find number of rotations in a circularly sorted array
  121. Search an element in a circular sorted array
  122. Find first or last occurrence of a given number in a sorted array
  123. Count occurrences of a number in a sorted array with duplicates
  124. Find smallest missing element from a sorted array
  125. Find Floor and Ceil of a number in a sorted array
  126. Search in a nearly sorted array in O(logn) time
  127. Find number of 1’s in a sorted binary array
  128. Find the peak element in an array
  129. Maximum Sum Subarray using Divide & Conquer
  130. Find Minimum and Maximum element in an array using minimum comparisons
  131. Matrix Chain Multiplication
  132. 0–1 Knapsack problem
  133. Maximize value of the expression
  134. Partition problem
  135. Subset sum problem
  136. Minimum Sum Partition problem
  137. Rod Cutting
  138. Coin change-making problem (unlimited supply of coins)
  139. Coin Change Problem (Total number of ways to get the denomination of coins)
  140. Longest alternating subsequence
  141. Combinations of words formed by replacing given numbers with corresponding alphabets
  142. Decode the given sequence to construct minimum number without repeated digits
  143. All combinations of elements satisfying given constraints
  144. Find Missing Term in a Sequence in log(n) time
  145. Print all distinct Subsets of a given Set
  146. Find Floor and Ceil of a number in a sorted array (Recursive solution)
  147. Set both elements of a binary array to 0 in single line
  148. K-Partition Problem | Printing all Partitions
  149. 3 Partition Problem
  150. 3-partition problem extended | Print all partitions
  151. Iterative Merge Sort Algorithm (Bottom-up Merge Sort)
  152. Find two duplicate elements in an limited range array (using XOR)
  153. Find missing number and duplicate elements in an array
  154. Find Minimum and Maximum element in an array by doing minimum comparisons
  155. Find Frequency of each element in a sorted array containing duplicates
  156. Difference between Subarray, Subsequence and Subset

Backtracking:

  1. Print all possible solutions to N Queens problem
  2. Print all Possible Knight’s Tours in a chessboard
  3. Find Shortest Path in Maze
  4. Find Longest Possible Route in a Matrix
  5. Find path from source to destination in a matrix that satisfies given constraints
  6. Find total number of unique paths in a maze from source to destination
  7. Print All Hamiltonian Path present in a graph
  8. Print all k-colorable configurations of the graph (Vertex coloring of graph)
  9. Find all Permutations of a given string
  10. All combinations of elements satisfying given constraints
  11. Find all binary strings that can be formed from given wildcard pattern
  12. K-Partition Problem | Printing all Partitions
  13. Magnet Puzzle
  14. Find ways to calculate a target from elements of specified array
  15. Find minimum number possible by doing at-most K swaps
  16. Determine if a pattern matches with a string or not

Binary:

  1. Bit Hacks — Part 1 (Basic)
  2. Bit Hacks — Part 2 (Playing with k’th bit)
  3. Bit Hacks — Part 3 (Playing with rightmost set bit of a number)
  4. Bit Hacks — Part 4 (Playing with letters of English alphabet)
  5. Bit Hacks — Part 5 (Find absolute value of an integer without branching)
  6. Bit Hacks — Part 6 (Random Problems)
  7. Brian Kernighan’s Algorithm to count set bits in an integer
  8. Compute parity of a number using lookup table
  9. Count set bits using lookup table
  10. Find the minimum or maximum of two integers without using branching
  11. Multiply 16-bit integers using 8-bit multiplier
  12. Round up to the next highest power of 2
  13. Round up to the previous power of 2
  14. Swap individual bits at given position in an integer
  15. Check if given number is power of 4 or not
  16. Reverse Bits of a given Integer
  17. Find odd occurring element in an array in single traversal
  18. Find two odd occurring element in an array without using any extra space
  19. Swap two bits at given position in an integer
  20. Add binary representation of two integers
  21. Swap Adjacent Bits of a Number
  22. Print all distinct Subsets of a given Set
  23. Perform Division of two numbers without using division operator (/)
  24. Check if adjacent bits are set in binary representation of a given number
  25. Conditionally negate a value without branching
  26. Find two duplicate elements in an limited range array (using XOR)
  27. Find missing number and duplicate elements in an array
  28. Check if given number is power of 8 or not
  29. Circular shift on binary representation of an integer by k positions
  30. Solve given set of problems without using multiplication or division operators
  31. Reverse Bits of an integer using lookup table
  32. Generate binary numbers between 1 to N
  33. Efficiently implement power function | Recursive and Iterative
  34. Find square of a number without using multiplication and division operator | 3 methods
  35. Generate power set of a given set
  36. Huffman Coding
  37. Find all odd occurring elements in an array having limited range of elements

Binary Tree:

  1. Check if two given binary trees are identical or not | Iterative & Recursive
  2. Calculate height of a binary tree | Iterative & Recursive
  3. Delete given Binary Tree | Iterative & Recursive
  4. Inorder Tree Traversal | Iterative & Recursive
  5. Preorder Tree Traversal | Iterative & Recursive
  6. Postorder Tree Traversal | Iterative & Recursive
  7. Level Order Traversal of Binary Tree
  8. Spiral Order Traversal of Binary Tree
  9. Reverse Level Order Traversal of Binary Tree
  10. Print all nodes of a given binary tree in specific order
  11. Print left view of binary tree
  12. Print Bottom View of Binary Tree
  13. Print Top View of Binary Tree
  14. Find next node in same level for given node in a binary tree
  15. Check if given binary tree is complete binary tree or not
  16. Determine if given two nodes are cousins of each other
  17. Print cousins of given node in a binary tree
  18. In-place convert given binary tree to its sum tree
  19. Check if given binary tree is a sum tree or not
  20. Combinations of words formed by replacing given numbers with corresponding alphabets
  21. Determine if given binary tree is a subtree of another binary tree or not
  22. Find diameter of a binary tree
  23. Check if given binary Tree has symmetric structure or not
  24. Convert binary tree to its mirror
  25. Check if binary tree can be converted to another by doing any no. of swaps of left & right child
  26. Find Lowest Common Ancestor (LCA) of two nodes in a binary tree
  27. Print all paths from root to leaf nodes in given binary tree
  28. Find ancestors of given node in a Binary Tree
  29. Find the distance between given pairs of nodes in a binary tree
  30. Find Vertical Sum in a given Binary Tree
  31. Print nodes in vertical order of a given Binary Tree (Vertical Traversal)
  32. Find the diagonal sum of given binary tree
  33. Print Diagonal Traversal of Binary Tree
  34. Print corner nodes of every level in binary tree
  35. In-place convert convert given Binary Tree to Doubly Linked List
  36. Sink nodes containing zero to the bottom of the binary tree
  37. Convert given binary tree to full tree by removing half nodes
  38. Truncate given binary tree to remove nodes which lie on a path having sum less than K
  39. Find maximum sum root-to-leaf path in a binary tree
  40. Check if given binary tree is height balanced or not
  41. Convert normal binary tree to Left-child right-sibling binary tree
  42. Determine if given Binary Tree is a BST or not
  43. Convert a Binary Tree to BST by maintaining its original structure
  44. Invert given Binary Tree | Recursive and Iterative solution
  45. Print Right View of a Binary Tree
  46. Print leaf to root path for every leaf node in a binary tree
  47. Find maximum width of given binary tree
  48. Build Binary Tree from given Parent array
  49. C++ Program to Print Binary Tree Structure
  50. Find all nodes at given distance from leaf nodes in a binary tree
  51. Count all subtrees having same value of nodes in a binary tree
  52. Find Maximum Difference Between a Node and its Descendants in a Binary Tree
  53. Construct a Binary Tree from Ancestor Matrix
  54. Calculate height of a binary tree with leaf nodes forming a circular doubly linked list

BST:

  1. Insertion in BST
  2. Search given key in BST
  3. Deletion from BST
  4. Construct balanced BST from given keys
  5. Determine if given Binary Tree is a BST or not
  6. Check if given keys represents same BSTs or not without building the BST
  7. Find inorder predecessor for given key in a BST
  8. Find Lowest Common Ancestor (LCA) of two nodes in a Binary Search Tree
  9. Find K’th smallest and K’th largest element in BST
  10. Floor and Ceil in a Binary Search Tree
  11. Find optimal cost to construct binary search tree
  12. Convert a Binary Tree to BST by maintaining its original structure
  13. Remove nodes from BST that have keys outside the valid range
  14. Find a pair with given sum in a BST
  15. Find inorder successor for given key in a BST
  16. Replace every element of an array with the least greater element on its right

Divide & Conquer:

  1. Binary Search
  2. Find number of rotations in a circularly sorted array
  3. Search an element in a circular sorted array
  4. Find first or last occurrence of a given number in a sorted array
  5. Count occurrences of a number in a sorted array with duplicates
  6. Find smallest missing element from a sorted array
  7. Find Floor and Ceil of a number in a sorted array
  8. Search in a nearly sorted array in O(logn) time
  9. Find number of 1’s in a sorted binary array
  10. Find the peak element in an array
  11. Maximum Sum Subarray using Divide & Conquer
  12. Find Minimum and Maximum element in an array using minimum comparisons
  13. Efficiently implement power function | Recursive and Iterative
  14. Find Missing Term in a Sequence in log(n) time
  15. Division of Two Numbers using Binary Search Algorithm
  16. Find Floor and Ceil of a number in a sorted array (Recursive solution)
  17. Find Minimum and Maximum element in an array by doing minimum comparisons
  18. Find Frequency of each element in a sorted array containing duplicates
  19. Ternary Search vs Binary search
  20. Exponential search
  21. Interpolation search
  22. Merge Sort Algorithm
  23. Iterative Merge Sort Algorithm (Bottom-up Merge Sort)
  24. Merge Sort Algorithm for Singly Linked List
  25. Inversion Count of an array
  26. Quicksort Algorithm
  27. Iterative Implementation of Quicksort
  28. Hybrid QuickSort
  29. Quicksort using Dutch National Flag Algorithm
  30. Quick Sort using Hoare’s Partitioning scheme

Dynamic Programming:

  1. Introduction to Dynamic Programming
  2. Longest Common Subsequence | Introduction & LCS Length
  3. Longest Common Subsequence | Space optimized version
  4. Longest Common Subsequence of K-sequences
  5. Longest Common Subsequence | Finding all LCS
  6. Longest Common Substring problem
  7. Longest Palindromic Subsequence using Dynamic Programming
  8. Longest Repeated Subsequence problem
  9. Implement Diff Utility
  10. Shortest Common Supersequence | Introduction & SCS Length
  11. Shortest Common Supersequence | Finding all SCS
  12. Shortest Common Supersequence | Using LCS
  13. Longest Increasing Subsequence using Dynamic Programming
  14. Longest Bitonic Subsequence
  15. Increasing Subsequence with Maximum Sum
  16. The Levenshtein distance (Edit distance) problem
  17. Find size of largest square sub-matrix of 1’s present in given binary matrix
  18. Matrix Chain Multiplication
  19. Find the minimum cost to reach last cell of the matrix from its first cell
  20. Find longest sequence formed by adjacent numbers in the matrix
  21. Count number of paths in a matrix with given cost to reach destination cell
  22. 0–1 Knapsack problem
  23. Maximize value of the expression
  24. Partition problem
  25. Subset sum problem
  26. Minimum Sum Partition problem
  27. Find all N-digit binary strings without any consecutive 1’s
  28. Rod Cutting
  29. Maximum Product Rod Cutting
  30. Coin change-making problem (unlimited supply of coins)
  31. Coin Change Problem — Find total number of ways to get the denomination of coins
  32. Total possible solutions to linear equation of k variables
  33. Longest alternating subsequence
  34. Count number of times a pattern appears in given string as a subsequence
  35. Collect maximum points in a matrix by satisfying given constraints
  36. Count total possible combinations of N-digit numbers in a mobile keypad
  37. Find optimal cost to construct binary search tree
  38. Word Break Problem
  39. Word Break Problem | Using Trie Data Structure
  40. Determine Minimal Adjustment Cost of an Array
  41. Check if a string is K-Palindrome or not
  42. Wildcard Pattern Matching
  43. Find probability that a person is alive after taking N steps on the island
  44. Calculate sum of all elements in a sub-matrix in constant time
  45. Find maximum sum K x K sub-matrix in a given M x N matrix
  46. Find maximum sum submatrix present in a given matrix
  47. Find maximum sum of subsequence with no adjacent elements
  48. Maximum subarray problem (Kadane’s algorithm)
  49. Single-Source Shortest Paths — Bellman Ford Algorithm
  50. All-Pairs Shortest Paths — Floyd Warshall Algorithm
  51. Longest Decreasing Subsequence Problem
  52. Pots of Gold Game using Dynamic Programming
  53. Find minimum cuts needed for palindromic partition of a string
  54. Maximum Length Snake Sequence
  55. 3 Partition Problem
  56. Calculate size of the largest plus of 1’s in binary matrix
  57. Check if given string is interleaving of two other given strings
  58. Longest Increasing Subsequence using LCS
  59. Determine negative-weight cycle in a graph

Graphs:

  1. Terminology and Representations of Graphs
  2. Graph Implementation using STL
  3. Graph Implementation in C++ without using STL
  4. Implement Graph Data Structure in C
  5. Graph Implementation in Java using Collections
  6. Breadth First Search (BFS) | Iterative & Recursive Implementation
  7. Depth First Search (DFS) | Iterative & Recursive Implementation
  8. Arrival and Departure Time of Vertices in DFS
  9. Types of edges involved in DFS and relation between them
  10. Bipartite Graph
  11. Determine if a given graph is Bipartite Graph using DFS
  12. Minimum number of throws required to win Snake and Ladder game
  13. Topological Sorting in a DAG
  14. Kahn’s Topological Sort Algorithm
  15. Transitive Closure of a Graph
  16. Check if an undirected graph contains cycle or not
  17. Total paths in given digraph from given source to destination having exactly m edges
  18. Determine if an undirected graph is a Tree (Acyclic Connected Graph)
  19. 2-Edge Connectivity in the graph
  20. 2-Vertex Connectivity in the graph
  21. Check if given digraph is a DAG (Directed Acyclic Graph) or not
  22. Disjoint-Set Data Structure (Union-Find Algorithm)
  23. Chess Knight Problem — Find Shortest path from source to destination
  24. Check if given Graph is Strongly Connected or not
  25. Check if given Graph is Strongly Connected or not using one DFS Traversal
  26. Union-Find Algorithm for Cycle Detection in undirected graph
  27. Kruskal’s Algorithm for finding Minimum Spanning Tree
  28. Single-Source Shortest Paths — Dijkstra’s Algorithm
  29. Single-Source Shortest Paths — Bellman Ford Algorithm
  30. All-Pairs Shortest Paths — Floyd Warshall Algorithm
  31. Find Cost of Shortest Path in DAG using one pass of Bellman-Ford
  32. Least Cost Path in Weighted Digraph using BFS
  33. Find maximum cost path in graph from given source to destination
  34. Determine negative-weight cycle in a graph
  35. Print all k-colorable configurations of the graph (Vertex coloring of graph)
  36. Print All Hamiltonian Path present in a graph
  37. Greedy coloring of graph

Heap:

  1. Introduction to Priority Queues using Binary Heaps
  2. Min Heap and Max Heap Implementation in C++
  3. Min Heap and Max Heap Implementation in Java
  4. Heap Sort
  5. Check if given array represents min heap or not
  6. Convert Max Heap to Min Heap in linear time
  7. Find K’th largest element in an array
  8. Sort a K-Sorted Array
  9. Merge M sorted lists of variable length
  10. Find K’th smallest element in an array
  11. Find smallest range with at-least one element from each of the given lists
  12. Merge M sorted lists each containing N elements
  13. External merge sort
  14. Huffman Coding
  15. Find first k maximum occurring words in given set of strings
  16. Find first k non-repeating characters in a string in single traversal

Linked List:

  1. Introduction to Linked Lists
  2. Linked List Implementation | Part 1
  3. Linked List Implementation | Part 2
  4. Static Linked List in C
  5. Clone given Linked List
  6. Delete Linked List
  7. Pop operation in linked list
  8. Insert given node into the correct sorted position in the given sorted linked list
  9. Given a linked list, change it to be in sorted order
  10. Split the nodes of the given linked list into front and back halves
  11. Remove duplicates from a sorted linked list
  12. Move front node of the given list to the front of the another list
  13. Move even nodes to the end of the list in reverse order
  14. Split given linked list into two lists where each list containing alternating elements from it
  15. Construct a linked list by merging alternate nodes of two given lists
  16. Merge given sorted linked lists into one
  17. Merge Sort Algorithm for Singly Linked List
  18. Intersection of two given sorted linked lists
  19. Reverse linked list | Part 1 (Iterative Solution)
  20. Reverse linked list | Part 2 (Recursive Solution)
  21. Reverse every group of k nodes in given linked list
  22. Find K’th node from the end in a linked list
  23. Merge alternate nodes of two linked lists into the first list
  24. Merge two sorted linked lists from their end
  25. Delete every N nodes in a linked list after skipping M nodes
  26. Rearrange linked list in specific manner in linear time
  27. Check if linked list is palindrome or not
  28. Move last node to front in a given Linked List
  29. Rearrange the linked list in specific manner
  30. Detect Cycle in a linked list (Floyd’s Cycle Detection Algorithm)
  31. Sort linked list containing 0’s, 1’s and 2’s
  32. Stack Implementation using Linked List
  33. Queue Implementation using Linked List
  34. Remove duplicates from a linked list
  35. Rearrange the linked list so that it has alternating high, low values
  36. Rearrange a Linked List by Separating Odd Nodes from the Even Ones
  37. Calculate height of a binary tree with leaf nodes forming a circular doubly linked list

Matrix:

  1. Print Matrix in Spiral Order
  2. Create Spiral Matrix from given array
  3. Shift all matrix elements by 1 in Spiral Order
  4. Find Shortest path from source to destination in a matrix that satisfies given constraints
  5. Change all elements of row i and column j in a matrix to 0 if cell (i, j) has value 0
  6. Print diagonal elements of the matrix having positive slope
  7. Find all paths from first cell to last cell of a matrix
  8. Replace all occurrences of 0 that are not surrounded by 1 in a binary matrix
  9. In-place rotate the matrix by 90 degrees in clock-wise direction
  10. Count negative elements present in sorted matrix in linear time
  11. Report all occurrences of an element in row wise and column wise sorted matrix in linear time
  12. Calculate sum of all elements in a sub-matrix in constant time
  13. Find maximum sum K x K sub-matrix in a given M x N matrix
  14. Find maximum sum submatrix present in a given matrix
  15. Find probability that a person is alive after taking N steps on the island
  16. Count the number of islands
  17. Flood fill Algorithm
  18. Find shortest safe route in a field with sensors present
  19. Find all occurrences of given string in a character matrix
  20. Shortest path in a Maze | Lee algorithm
  21. Check if given matrix is Toeplitz matrix or not
  22. In-place rotate the matrix by 180 degrees
  23. Fill Binary Matrix with Alternating Rectangles of 0 and 1
  24. Find all common elements present in every row of given matrix
  25. Construct a Binary Tree from Ancestor Matrix
  26. Find common elements present in all rows of a matrix
  27. Travelling Salesman Problem using Branch and Bound
  28. Collect maximum points in a matrix by satisfying given constraints
  29. Count number of paths in a matrix with given cost to reach destination cell
  30. Find longest sequence formed by adjacent numbers in the matrix
  31. Find the minimum cost to reach last cell of the matrix from its first cell
  32. Matrix Chain Multiplication
  33. Find size of largest square sub-matrix of 1’s present in given binary matrix
  34. Chess Knight Problem — Find Shortest path from source to destination
  35. Find Duplicate rows in a binary matrix
  36. Print all possible solutions to N Queens problem
  37. Print all Possible Knight’s Tours in a chessboard
  38. Find Shortest Path in Maze
  39. Find Longest Possible Route in a Matrix
  40. Calculate size of the largest plus of 1’s in binary matrix
  41. Find the maximum value of M[c][d] — M[a][b] over all choices of indexes
  42. Find shortest distance of every cell from landmine in a Maze
  43. Find shortest route in a device to construct the given string

Queue:

  1. Queue Implementation
  2. Queue Implementation using Linked List
  3. Chess Knight Problem — Find Shortest path from source to destination
  4. Shortest path in a Maze | Lee algorithm
  5. Find shortest safe route in a field with sensors present
  6. Flood fill Algorithm
  7. Count the number of islands
  8. Find Shortest path from source to destination in a matrix that satisfies given constraints
  9. Generate binary numbers between 1 to N
  10. Calculate height of a binary tree | Iterative & Recursive
  11. Delete given Binary Tree | Iterative & Recursive
  12. Level Order Traversal of Binary Tree
  13. Spiral Order Traversal of Binary Tree
  14. Reverse Level Order Traversal of Binary Tree
  15. Print all nodes of a given binary tree in specific order
  16. Print left view of binary tree
  17. Find next node in same level for given node in a binary tree
  18. Check if given binary tree is complete binary tree or not
  19. Print Diagonal Traversal of Binary Tree
  20. Print corner nodes of every level in binary tree
  21. Breadth First Search (BFS) | Iterative & Recursive Implementation
  22. Minimum number of throws required to win Snake and Ladder game
  23. Check if an undirected graph contains cycle or not
  24. Invert given Binary Tree | Recursive and Iterative solution
  25. Find maximum cost path in graph from given source to destination
  26. Find shortest distance of every cell from landmine in a Maze

Sorting:

  1. Insertion sort | Iterative & Recursive
  2. Selection sort | Iterative & Recursive
  3. Bubble sort | Iterative & Recursive
  4. Merge Sort Algorithm
  5. Iterative Merge Sort Algorithm (Bottom-up Merge Sort)
  6. Quicksort Algorithm
  7. Iterative Implementation of Quicksort
  8. Hybrid QuickSort
  9. Quicksort using Dutch National Flag Algorithm
  10. Quick Sort using Hoare’s Partitioning scheme
  11. External merge sort
  12. Counting Sort Algorithm
  13. Custom Sort | Sort elements by their frequency and Index
  14. Custom Sort | Sort elements of the array by order of elements defined by the second array
  15. Inversion Count of an array
  16. Segregate positive and negative integers in linear time
  17. Efficiently Sort an Array with many Duplicated Values
  18. Find the smallest window in array sorting which will make the entire array sorted
  19. Find largest number possible from set of given numbers
  20. Move all zeros present in the array to the end
  21. Sort binary array in linear time
  22. Sort linked list containing 0’s, 1’s and 2’s
  23. Merge Sort Algorithm for Singly Linked List
  24. Group anagrams together from given list of words
  25. Activity Selection Problem
  26. Lexicographic sorting of given set of keys
  27. Heap Sort
  28. Merge M sorted lists of variable length
  29. Merge M sorted lists each containing N elements
  30. Find all palindromic permutations of a string
  31. Find all lexicographically next permutations of a string sorted in ascending order
  32. Merge two sorted linked lists from their end
  33. Sort an array containing 0’s, 1’s and 2’s (Dutch national flag problem)
  34. Find pair with given sum in the array
  35. Inplace merge two sorted arrays
  36. Merge two arrays by satisfying given constraints
  37. Find maximum product of two integers in an array
  38. Find all distinct combinations of given length
  39. Find all distinct combinations of given length with repetition allowed
  40. Merging Overlapping Intervals
  41. Print all quadruplets with given sum | 4-sum problem extended
  42. 4 sum problem | Quadruplets with given sum
  43. Find two numbers with maximum sum formed by array digits
  44. Find a Triplet having Maximum Product in an Array
  45. Find Minimum Product among all Combinations of Triplets in an Array
  46. Find all distinct combinations of given length — Part 2
  47. Find the surpasser count for each element of an array

Stack:

  1. Stack Implementation
  2. Stack Implementation using Linked List
  3. Check if given expression is balanced expression or not
  4. Find duplicate parenthesis in an expression
  5. Evaluate given postfix expression
  6. Decode the given sequence to construct minimum number without repeated digits
  7. Inorder Tree Traversal | Iterative & Recursive
  8. Preorder Tree Traversal | Iterative & Recursive
  9. Postorder Tree Traversal | Iterative & Recursive
  10. Find ancestors of given node in a Binary Tree
  11. Check if two given binary trees are identical or not | Iterative & Recursive
  12. Reverse given text without reversing the individual words
  13. Find all binary strings that can be formed from given wildcard pattern
  14. Iterative Implementation of Quicksort
  15. Depth First Search (DFS) | Iterative & Recursive Implementation
  16. Invert given Binary Tree | Recursive and Iterative solution
  17. Print leaf to root path for every leaf node in a binary tree

String:

  1. Check if given string is a rotated palindrome or not
  2. Longest Palindromic Substring (Non-DP Space Optimized Solution)
  3. Check if repeated subsequence is present in the string or not
  4. Check if strings can be derived from each other by circularly rotating them
  5. Check if given set of moves is circular or not
  6. Convert given number into corresponding excel column name
  7. Determine if two strings are anagram or not
  8. Find all binary strings that can be formed from given wildcard pattern
  9. Find all interleavings of given strings
  10. Isomorphic Strings
  11. Find all possible palindromic substrings in a string
  12. Find all possible combinations of words formed from mobile keypad
  13. Find all possible combinations by replacing given digits with characters of the corresponding list
  14. Find all words from given list that follows same order of characters as given pattern
  15. Find first k non-repeating characters in a string in single traversal
  16. Group anagrams together from given list of words
  17. Introduction to Pattern Matching
  18. Inplace remove all occurrences of ‘AB’ and ‘C’ from the string
  19. Longest even length palidromic sum substring
  20. Print string in zig-zag form in k rows
  21. Reverse given text without reversing the individual words
  22. Run Length Encoding (RLE) data compression algorithm
  23. Validate an IP address
  24. Find the longest substring of given string containing k distinct characters
  25. Find all palindromic permutations of a string
  26. Find all substrings of a string that are permutation of a given string
  27. Find the longest substring of given string containing all distinct characters
  28. Find all Permutations of a given string
  29. Iterative Approach to find Permutations of a String in C++ and Java
  30. Generate all Permutations of a String in Java | Recursive & Iterative
  31. Find all lexicographically next permutations of a string sorted in ascending order
  32. Find Lexicographically minimal string rotation
  33. Find all strings of given length containing balanced parentheses
  34. Find all N-digit strictly increasing numbers (Bottom-Up and Top-Down Approach)
  35. Find all N-digit binary numbers having more 1’s than 0’s for any prefix
  36. Find all N-digit numbers with given sum of digits
  37. Find all N-digit binary numbers with k-bits set where k ranges from 1 to N
  38. Generate binary numbers between 1 to N
  39. Find all combinations of non-overlapping substrings of a string
  40. Check if given sentence is syntactically correct or not
  41. Calculate rank of given string among all its lexicographically sorted permutations
  42. Find all Lexicographic Permutations of a String
  43. Find all N-digit binary numbers with equal sum of bits in its two halves
  44. Check if given string is interleaving of two other given strings
  45. Difference between Subarray, Subsequence and Subset
  46. std::next_permutation | Overview & Implementation in C++
  47. std::prev_permutation | Overview & Implementation in C++
  48. Implementation of KMP Algorithm in C, C++ and Java
  49. Reverse String without using Recursion
  50. Reverse given string using Recursion
  51. Reverse a String in Java in 10 different ways
  52. Determine if a given string is palindrome or not
  53. In-place remove all adjacent duplicates from the given string
  54. Find the minimum number of inversions needed to make the given expression balanced
  55. Replace all non-overlapping occurrences of the pattern
  56. Construct the longest palindrome by shuffling or deleting characters from a string
  57. Determine if characters of a String follows a specified order or not
  58. Print all combinations of phrases that can be formed by picking words from each of the given lists
  59. Remove all extra spaces from a string
  60. Break a string into all possible combinations of non-overlapping substrings
  61. Remove adjacent duplicate characters from a string
  62. Combinations of words formed by replacing given numbers with corresponding alphabets
  63. Word Break Problem
  64. Wildcard Pattern Matching
  65. Count number of times a pattern appears in given string as a subsequence
  66. The Levenshtein distance (Edit distance) problem
  67. Longest Common Subsequence | Introduction & LCS Length
  68. Longest Common Subsequence | Space optimized version
  69. Longest Common Subsequence of K-sequences
  70. Longest Common Subsequence | Finding all LCS
  71. Longest Repeated Subsequence problem
  72. Longest Palindromic Subsequence using Dynamic Programming
  73. Longest Common Substring problem
  74. Shortest Common Supersequence | Introduction & SCS Length
  75. Shortest Common Supersequence | Finding all SCS
  76. Shortest Common Supersequence | Using LCS
  77. Implement Diff Utility
  78. Word Break Problem | Using Trie Data Structure
  79. Find minimum cuts needed for palindromic partition of a string
  80. Check if a string is K-Palindrome or not
  81. Find shortest route in a device to construct the given string
  82. Find minimum number possible by doing at-most K swaps
  83. Determine if a pattern matches with a string or not

Trie:

  1. Trie Implementation | Insert, Search and Delete
  2. Memory efficient Trie Implementation using Map | Insert, Search and Delete
  3. C++ Implementation of Trie Data Structure
  4. Longest Common Prefix in given set of strings (using Trie)
  5. Lexicographic sorting of given set of keys
  6. Find maximum occurring word in given set of strings
  7. Find first k maximum occurring words in given set of strings
  8. Find Duplicate rows in a binary matrix
  9. Word Break Problem | Using Trie Data Structure

Greedy:

  1. Activity Selection Problem
  2. Huffman Coding
  3. Shortest Superstring Problem
  4. Job Sequencing Problem with Deadlines
  5. Greedy coloring of graph
  6. Kruskal’s Algorithm for finding Minimum Spanning Tree
  7. Single-Source Shortest Paths — Dijkstra’s Algorithm

Puzzles:

  1. Clock angle problem — Find angle between hour and minute hand
  2. Add two numbers without using addition operator | 4 methods
  3. Generate power set of a given set
  4. Implement power function without using multiplication and division operators
  5. Print all numbers between 1 to N without using semicolon
  6. Swap two numbers without using third variable | 5 methods
  7. Determine the if condition to print specific output
  8. Find maximum, minimum of three numbers without using conditional statement and ternary operator | 4 methods
  9. Find numbers represented as sum of two cubes for two different pairs
  10. Print “Hello World” with empty main() function | 3 methods
  11. Tower of Hanoi Problem
  12. Print all numbers between 1 to N without using any loop | 4 methods
  13. Print a semicolon without using semicolon anywhere in the program
  14. Multiply two numbers without using multiplication operator or loops
  15. Find square of a number without using multiplication and division operator | 3 methods
  16. Find if a number is even or odd without using any conditional statement
  17. Set both elements of a binary array to 0 in single line
  18. Find minimum number without using conditional statement or ternary operator
  19. Perform Division of two numbers without using division operator (/)
  20. Generate 0 and 1 with 75% and 25% Probability
  21. Generate Desired Random Numbers With Equal Probability
  22. Return 0, 1 and 2 with equal Probability using the specified function
  23. Generate Fair Results from a Biased Coin
  24. Generate numbers from 1 to 7 with equal probability using specified function
  25. Implement Ternary Operator Without Using Conditional Expressions
  26. Determine if two integers are equal without using comparison and arithmetic operators
  27. Return 0 and 1 with equal Probability using the specified function
  28. Generate Random Input from an Array according to given Probabilities
  29. Generate Fair Results from a Biased Coin
  30. Magnet Puzzle