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Mohit Jaisal
Mohit Jaisal

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Complete Data Structures and Algorithms Questions in sequence || DS & Algo Questions for Practice of all types

All the Questions listed here is in sequence to build your interest in DSA and after completing these Questions you will be able to solve all types of DSA Questions

Topic Problems
Array Reverse the array
Array Find the maximum and minimum element in an array
Array Find the "Kth" max and min element of an array
Array Given an array which consists of only 0, 1 and 2. Sort the array without using any sorting algo
Array Move all the negative elements to one side of the array
Array Find the Union and Intersection of the two sorted arrays.
Array Write a program to cyclically rotate an array by one.
Array find Largest sum contiguous Subarray [V. IMP]
Array Minimise the maximum difference between heights [V.IMP]
Array Minimum no. of Jumps to reach end of an array
Array find duplicate in an array of N+1 Integers
Array Merge 2 sorted arrays without using Extra space.
Array Kadane's Algo [V.V.V.V.V IMP]
Array Merge Intervals
Array Next Permutation
Array Count Inversion
Array Best time to buy and Sell stock
Array find all pairs on integer array whose sum is equal to given number
Array find common elements In 3 sorted arrays
Array Rearrange the array in alternating positive and negative items with O(1) extra space
Array Find if there is any subarray with sum equal to 0
Array Find factorial of a large number
Array find maximum product subarray
Array Find longest coinsecutive subsequence
Array Given an array of size n and a number k, fin all elements that appear more than " n/k " times.
Array Maximum profit by buying and selling a share atmost twice
Array Find whether an array is a subset of another array
Array Find the triplet that sum to a given value
Array Trapping Rain water problem
Array Chocolate Distribution problem
Array Smallest Subarray with sum greater than a given value
Array Three way partitioning of an array around a given value
Array Minimum swaps required bring elements less equal K together
Array Minimum no. of operations required to make an array palindrome
Array Median of 2 sorted arrays of equal size
Array Median of 2 sorted arrays of different size
Matrix Spiral traversal on a Matrix
Matrix Search an element in a matriix
Matrix Find median in a row wise sorted matrix
Matrix Find row with maximum no. of 1's
Matrix Print elements in sorted order using row-column wise sorted matrix
Matrix Maximum size rectangle
Matrix Find a specific pair in matrix
Matrix Rotate matrix by 90 degrees
Matrix Kth smallest element in a row-cpumn wise sorted matrix
Matrix Common elements in all rows of a given matrix
String Reverse a String
String Check whether a String is Palindrome or not
String Find Duplicate characters in a string
String Why strings are immutable in Java?
String Write a Code to check whether one string is a rotation of another
String Write a Program to check whether a string is a valid shuffle of two strings or not
String Count and Say problem
String Write a program to find the longest Palindrome in a string.[ Longest palindromic Substring]
String Find Longest Recurring Subsequence in String
String Print all Subsequences of a string.
String Print all the permutations of the given string
String Split the Binary string into two substring with equal 0’s and 1’s
String Word Wrap Problem [VERY IMP].
String EDIT Distance [Very Imp]
String Find next greater number with same set of digits. [Very Very IMP]
String Balanced Parenthesis problem.[Imp]
String Word break Problem[ Very Imp]
String Rabin Karp Algo
String KMP Algo
String Convert a Sentence into its equivalent mobile numeric keypad sequence.
String Minimum number of bracket reversals needed to make an expression balanced.
String Count All Palindromic Subsequence in a given String.
String Count of number of given string in 2D character array
String Search a Word in a 2D Grid of characters.
String Boyer Moore Algorithm for Pattern Searching.
String Converting Roman Numerals to Decimal
String Longest Common Prefix
String Number of flips to make binary string alternate
String Find the first repeated word in string.
String Minimum number of swaps for bracket balancing.
String Find the longest common subsequence between two strings.
String Program to generate all possible valid IP addresses from given string.
String Write a program tofind the smallest window that contains all characters of string itself.
String Rearrange characters in a string such that no two adjacent are same
String Minimum characters to be added at front to make string palindrome
String Given a sequence of words, print all anagrams together
String Find the smallest window in a string containing all characters of another string
String Recursively remove all adjacent duplicates
String String matching where one string contains wildcard characters
String Function to find Number of customers who could not get a computer
String Transform One String to Another using Minimum Number of Given Operation
String Check if two given strings are isomorphic to each other
String Recursively print all sentences that can be formed from list of word lists
Searching & Sorting Find first and last positions of an element in a sorted array
Searching & Sorting Find a Fixed Point (Value equal to index) in a given array
Searching & Sorting Search in a rotated sorted array
Searching & Sorting square root of an integer
Searching & Sorting Maximum and minimum of an array using minimum number of comparisons
Searching & Sorting Optimum location of point to minimize total distance
Searching & Sorting Find the repeating and the missing
Searching & Sorting find majority element
Searching & Sorting Searching in an array where adjacent differ by at most k
Searching & Sorting find a pair with a given difference
Searching & Sorting find four elements that sum to a given value
Searching & Sorting maximum sum such that no 2 elements are adjacent
Searching & Sorting Count triplet with sum smaller than a given value
Searching & Sorting merge 2 sorted arrays
Searching & Sorting print all subarrays with 0 sum
Searching & Sorting Product array Puzzle
Searching & Sorting Sort array according to count of set bits
Searching & Sorting minimum no. of swaps required to sort the array
Searching & Sorting Bishu and Soldiers
Searching & Sorting Rasta and Kheshtak
Searching & Sorting Kth smallest number again
Searching & Sorting Find pivot element in a sorted array
Searching & Sorting K-th Element of Two Sorted Arrays
Searching & Sorting Aggressive cows
Searching & Sorting Book Allocation Problem
Searching & Sorting EKOSPOJ:
Searching & Sorting Job Scheduling Algo
Searching & Sorting Missing Number in AP
Searching & Sorting Smallest number with atleastn trailing zeroes infactorial
Searching & Sorting Painters Partition Problem:
Searching & Sorting ROTI-Prata SPOJ
Searching & Sorting DoubleHelix SPOJ
Searching & Sorting Subset Sums
Searching & Sorting Findthe inversion count
Searching & Sorting Implement Merge-sort in-place
Searching & Sorting Partitioning and Sorting Arrays with Many Repeated Entries
LinkedList Write a Program to reverse the Linked List. (Both Iterative and recursive)
LinkedList Reverse a Linked List in group of Given Size. [Very Imp]
LinkedList Write a program to Detect loop in a linked list.
LinkedList Write a program to Delete loop in a linked list.
LinkedList Find the starting point of the loop. 
LinkedList Remove Duplicates in a sorted Linked List.
LinkedList Remove Duplicates in a Un-sorted Linked List.
LinkedList Write a Program to Move the last element to Front in a Linked List.
LinkedList Add “1” to a number represented as a Linked List.
LinkedList Add two numbers represented by linked lists.
LinkedList Intersection of two Sorted Linked List.
LinkedList Intersection Point of two Linked Lists.
LinkedList Merge Sort For Linked lists.[Very Important]
LinkedList Quicksort for Linked Lists.[Very Important]
LinkedList Find the middle Element of a linked list.
LinkedList Check if a linked list is a circular linked list.
LinkedList Split a Circular linked list into two halves.
LinkedList Write a Program to check whether the Singly Linked list is a palindrome or not.
LinkedList Deletion from a Circular Linked List.
LinkedList Reverse a Doubly Linked list.
LinkedList Find pairs with a given sum in a DLL.
LinkedList Count triplets in a sorted DLL whose sum is equal to given value “X”.
LinkedList Sort a “k”sorted Doubly Linked list.[Very IMP]
LinkedList Rotate DoublyLinked list by N nodes.
LinkedList Rotate a Doubly Linked list in group of Given Size.[Very IMP]
LinkedList Can we reverse a linked list in less than O(n) ?
LinkedList Why Quicksort is preferred for. Arrays and Merge Sort for LinkedLists ?
LinkedList Flatten a Linked List
LinkedList Sort a LL of 0's, 1's and 2's
LinkedList Clone a linked list with next and random pointer
LinkedList Merge K sorted Linked list
LinkedList Multiply 2 no. represented by LL
LinkedList Delete nodes which have a greater value on right side
LinkedList Segregate even and odd nodes in a Linked List
LinkedList Program for n’th node from the end of a Linked List
LinkedList Find the first non-repeating character from a stream of characters
Binary Trees level order traversal
Binary Trees Reverse Level Order traversal
Binary Trees Height of a tree
Binary Trees Diameter of a tree
Binary Trees Mirror of a tree
Binary Trees Inorder Traversal of a tree both using recursion and Iteration
Binary Trees Preorder Traversal of a tree both using recursion and Iteration
Binary Trees Postorder Traversal of a tree both using recursion and Iteration
Binary Trees Left View of a tree
Binary Trees Right View of Tree
Binary Trees Top View of a tree
Binary Trees Bottom View of a tree
Binary Trees Zig-Zag traversal of a binary tree
Binary Trees Check if a tree is balanced or not
Binary Trees Diagnol Traversal of a Binary tree
Binary Trees Boundary traversal of a Binary tree
Binary Trees Construct Binary Tree from String with Bracket Representation
Binary Trees Convert Binary tree into Doubly Linked List
Binary Trees Convert Binary tree into Sum tree
Binary Trees Construct Binary tree from Inorder and preorder traversal
Binary Trees Find minimum swaps required to convert a Binary tree into BST
Binary Trees Check if Binary tree is Sum tree or not
Binary Trees Check if all leaf nodes are at same level or not
Binary Trees Check if a Binary Tree contains duplicate subtrees of size 2 or more [ IMP ]
Binary Trees Check if 2 trees are mirror or not
Binary Trees Sum of Nodes on the Longest path from root to leaf node
Binary Trees Check if given graph is tree or not. [ IMP ]
Binary Trees Find Largest subtree sum in a tree
Binary Trees Maximum Sum of nodes in Binary tree such that no two are adjacent
Binary Trees Print all "K" Sum paths in a Binary tree
Binary Trees Find LCA in a Binary tree
Binary Trees Find distance between 2 nodes in a Binary tree
Binary Trees Kth Ancestor of node in a Binary tree
Binary Trees Find all Duplicate subtrees in a Binary tree [ IMP ]
Binary Trees Tree Isomorphism Problem
Binary Search Trees Fina a value in a BST
Binary Search Trees Deletion of a node in a BST
Binary Search Trees Find min and max value in a BST
Binary Search Trees Find inorder successor and inorder predecessor in a BST
Binary Search Trees Check if a tree is a BST or not
Binary Search Trees Populate Inorder successor of all nodes
Binary Search Trees Find LCA of 2 nodes in a BST
Binary Search Trees Construct BST from preorder traversal
Binary Search Trees Convert Binary tree into BST
Binary Search Trees Convert a normal BST into a Balanced BST
Binary Search Trees Merge two BST [ V.V.V>IMP ]
Binary Search Trees Find Kth largest element in a BST
Binary Search Trees Find Kth smallest element in a BST
Binary Search Trees Count pairs from 2 BST whose sum is equal to given value "X"
Binary Search Trees Find the median of BST in O(n) time and O(1) space
Binary Search Trees Count BST ndoes that lie in a given range
Binary Search Trees Replace every element with the least greater element on its right
Binary Search Trees Given "n" appointments, find the conflicting appointments
Binary Search Trees Check preorder is valid or not
Binary Search Trees Check whether BST contains Dead end
Binary Search Trees Largest BST in a Binary Tree [ V.V.V.V.V IMP ]
Binary Search Trees Flatten BST to sorted list
Greedy Activity Selection Problem
Greedy Job SequencingProblem
Greedy Huffman Coding
Greedy Water Connection Problem
Greedy Fractional Knapsack Problem
Greedy Greedy Algorithm to find Minimum number of Coins
Greedy Maximum trains for which stoppage can be provided
Greedy Minimum Platforms Problem
Greedy Buy Maximum Stocks if i stocks can be bought on i-th day
Greedy Find the minimum and maximum amount to buy all N candies
Greedy Minimize Cash Flow among a given set of friends who have borrowed money from each other
Greedy Minimum Cost to cut a board into squares
Greedy Check if it is possible to survive on Island
Greedy Find maximum meetings in one room
Greedy Maximum product subset of an array
Greedy Maximize array sum after K negations
Greedy Maximize the sum of arr[i]*i
Greedy Maximum sum of absolute difference of an array
Greedy Maximize sum of consecutive differences in a circular array
Greedy Minimum sum of absolute difference of pairs of two arrays
Greedy Program for Shortest Job First (or SJF) CPU Scheduling
Greedy Program for Least Recently Used (LRU) Page Replacement algorithm
Greedy Smallest subset with sum greater than all other elements
Greedy Chocolate Distribution Problem
Greedy DEFKIN -Defense of a Kingdom
Greedy GERGOVIA -Wine trading in Gergovia
Greedy Picking Up Chicks
Greedy CHOCOLA –Chocolate
Greedy ARRANGE -Arranging Amplifiers
Greedy K Centers Problem
Greedy Minimum Cost of ropes
Greedy Find smallest number with given number of digits and sum of digits
Greedy Rearrange characters in a string such that no two adjacent are same
Greedy Find maximum sum possible equal sum of three stacks
BackTracking Rat in a maze Problem
BackTracking Printing all solutions in N-Queen Problem
BackTracking Word Break Problem using Backtracking
BackTracking Remove Invalid Parentheses
BackTracking Sudoku Solver
BackTracking m Coloring Problem
BackTracking Print all palindromic partitions of a string
BackTracking Subset Sum Problem
BackTracking The Knight’s tour problem
BackTracking Tug of War
BackTracking Find shortest safe route in a path with landmines
BackTracking Combinational Sum
BackTracking Find Maximum number possible by doing at-most K swaps
BackTracking Print all permutations of a string
BackTracking Find if there is a path of more than k length from a source
BackTracking Longest Possible Route in a Matrix with Hurdles
BackTracking Print all possible paths from top left to bottom right of a mXn matrix
BackTracking Partition of a set intoK subsets with equal sum
BackTracking Find the K-th Permutation Sequence of first N natural numbers
Stacks & Queues  Implement Stack from Scratch
Stacks & Queues  Implement Queue from Scratch
Stacks & Queues Implement 2 stack in an array
Stacks & Queues find the middle element of a stack
Stacks & Queues Implement "N" stacks in an Array
Stacks & Queues Check the expression has valid or Balanced parenthesis or not.
Stacks & Queues Reverse a String using Stack
Stacks & Queues Design a Stack that supports getMin() in O(1) time and O(1) extra space.
Stacks & Queues Find the next Greater element
Stacks & Queues The celebrity Problem
Stacks & Queues Arithmetic Expression evaluation
Stacks & Queues Evaluation of Postfix expression
Stacks & Queues Implement a method to insert an element at its bottom without using any other data structure.
Stacks & Queues Reverse a stack using recursion
Stacks & Queues Sort a Stack using recursion
Stacks & Queues Merge Overlapping Intervals
Stacks & Queues Largest rectangular Area in Histogram
Stacks & Queues Length of the Longest Valid Substring
Stacks & Queues Expression contains redundant bracket or not
Stacks & Queues Implement Stack using Queue
Stacks & Queues Implement Stack using Deque
Stacks & Queues Stack Permutations (Check if an array is stack permutation of other)
Stacks & Queues Implement Queue using Stack
Stacks & Queues Implement "n" queue in an array
Stacks & Queues Implement a Circular queue
Stacks & Queues LRU Cache Implementationa
Stacks & Queues Reverse a Queue using recursion
Stacks & Queues Reverse the first “K” elements of a queue
Stacks & Queues Interleave the first half of the queue with second half
Stacks & Queues Find the first circular tour that visits all Petrol Pumps
Stacks & Queues Minimum time required to rot all oranges
Stacks & Queues Distance of nearest cell having 1 in a binary matrix
Stacks & Queues First negative integer in every window of size “k”
Stacks & Queues Check if all levels of two trees are anagrams or not.
Stacks & Queues Sum of minimum and maximum elements of all subarrays of size “k”.
Stacks & Queues Minimum sum of squares of character counts in a given string after removing “k” characters.
Stacks & Queues Queue based approach or first non-repeating character in a stream.
Stacks & Queues Next Smaller Element
Heap Implement a Maxheap/MinHeap using arrays and recursion.
Heap Sort an Array using heap. (HeapSort)
Heap Maximum of all subarrays of size k.
Heap “k” largest element in an array
Heap Kth smallest and largest element in an unsorted array
Heap Merge “K” sorted arrays. [ IMP ]
Heap Merge 2 Binary Max Heaps
Heap Kth largest sum continuous subarrays
Heap Leetcode- reorganize strings
Heap Merge “K” Sorted Linked Lists [V.IMP]
Heap Smallest range in “K” Lists
Heap Median in a stream of Integers
Heap Check if a Binary Tree is Heap
Heap Connect “n” ropes with minimum cost
Heap Convert BST to Min Heap
Heap Convert min heap to max heap
Heap Rearrange characters in a string such that no two adjacent are same.
Heap Minimum sum of two numbers formed from digits of an array
Graph Create a Graph, print it
Graph Implement BFS algorithm
Graph Implement DFS Algo
Graph Detect Cycle in Directed Graph using BFS/DFS Algo
Graph Detect Cycle in UnDirected Graph using BFS/DFS Algo
Graph Search in a Maze
Graph Minimum Step by Knight
Graph flood fill algo
Graph Clone a graph
Graph Making wired Connections
Graph word Ladder
Graph Dijkstra algo
Graph Implement Topological Sort
Graph Minimum time taken by each job to be completed given by a Directed Acyclic Graph
Graph Find whether it is possible to finish all tasks or not from given dependencies
Graph Find the no. of Isalnds
Graph Given a sorted Dictionary of an Alien Language, find order of characters
Graph Implement Kruksal’sAlgorithm
Graph Implement Prim’s Algorithm
Graph Total no. of Spanning tree in a graph
Graph Implement Bellman Ford Algorithm
Graph Implement Floyd warshallAlgorithm
Graph Travelling Salesman Problem
Graph Graph ColouringProblem
Graph Snake and Ladders Problem
Graph Find bridge in a graph
Graph Count Strongly connected Components(Kosaraju Algo)
Graph Check whether a graph is Bipartite or Not
Graph Detect Negative cycle in a graph
Graph Longest path in a Directed Acyclic Graph
Graph Journey to the Moon
Graph Cheapest Flights Within K Stops
Graph Oliver and the Game
Graph Water Jug problem using BFS
Graph Water Jug problem using BFS
Graph Find if there is a path of more thank length from a source
Graph M-ColouringProblem
Graph Minimum edges to reverse o make path from source to destination
Graph Paths to travel each nodes using each edge(Seven Bridges)
Graph Vertex Cover Problem
Graph Chinese Postman or Route Inspection
Graph Number of Triangles in a Directed and Undirected Graph
Graph Minimise the cashflow among a given set of friends who have borrowed money from each other
Graph Two Clique Problem
Trie Construct a trie from scratch
Trie Find shortest unique prefix for every word in a given list
Trie Word Break Problem | (Trie solution)
Trie Given a sequence of words, print all anagrams together
Trie Implement a Phone Directory
Trie Print unique rows in a given boolean matrix
Dynamic Programming Coin ChangeProblem
Dynamic Programming Knapsack Problem
Dynamic Programming Binomial CoefficientProblem
Dynamic Programming Permutation CoefficientProblem
Dynamic Programming Program for nth Catalan Number
Dynamic Programming Matrix Chain Multiplication 
Dynamic Programming Edit Distance
Dynamic Programming Subset Sum Problem
Dynamic Programming Friends Pairing Problem
Dynamic Programming Gold Mine Problem
Dynamic Programming Assembly Line SchedulingProblem
Dynamic Programming Painting the Fenceproblem
Dynamic Programming Maximize The Cut Segments
Dynamic Programming Longest Common Subsequence
Dynamic Programming Longest Repeated Subsequence
Dynamic Programming Longest Increasing Subsequence
Dynamic Programming Space Optimized Solution of LCS
Dynamic Programming LCS (Longest Common Subsequence) of three strings
Dynamic Programming Maximum Sum Increasing Subsequence
Dynamic Programming Count all subsequences having product less than K
Dynamic Programming Longest subsequence such that difference between adjacent is one
Dynamic Programming Maximum subsequence sum such that no three are consecutive
Dynamic Programming Egg Dropping Problem
Dynamic Programming Maximum Length Chain of Pairs
Dynamic Programming Maximum size square sub-matrix with all 1s
Dynamic Programming Maximum sum of pairs with specific difference
Dynamic Programming Min Cost PathProblem
Dynamic Programming Maximum difference of zeros and ones in binary string
Dynamic Programming Minimum number of jumps to reach end
Dynamic Programming Minimum cost to fill given weight in a bag
Dynamic Programming Minimum removals from array to make max –min <= K
Dynamic Programming Longest Common Substring
Dynamic Programming Count number of ways to reacha given score in a game
Dynamic Programming Count Balanced Binary Trees of Height h
Dynamic Programming LargestSum Contiguous Subarray [V>V>V>V IMP ]
Dynamic Programming Smallest sum contiguous subarray
Dynamic Programming Unbounded Knapsack (Repetition of items allowed)
Dynamic Programming Word Break Problem
Dynamic Programming Largest Independent Set Problem
Dynamic Programming Partition problem
Dynamic Programming Longest Palindromic Subsequence
Dynamic Programming Count All Palindromic Subsequence in a given String
Dynamic Programming Longest Palindromic Substring
Dynamic Programming Longest alternating subsequence
Dynamic Programming Weighted Job Scheduling
Dynamic Programming Coin game winner where every player has three choices
Dynamic Programming Count Derangements (Permutation such that no element appears in its original position) [ IMPORTANT ]
Dynamic Programming Maximum profit by buying and selling a share at most twice [ IMP ]
Dynamic Programming Optimal Strategy for a Game
Dynamic Programming Optimal Binary Search Tree
Dynamic Programming Palindrome PartitioningProblem
Dynamic Programming Word Wrap Problem
Dynamic Programming Mobile Numeric Keypad Problem [ IMP ]
Dynamic Programming Boolean Parenthesization Problem
Dynamic Programming Largest rectangular sub-matrix whose sum is 0
Dynamic Programming Largest area rectangular sub-matrix with equal number of 1’s and 0’s [ IMP ]
Dynamic Programming Maximum sum rectangle in a 2D matrix
Dynamic Programming Maximum profit by buying and selling a share at most k times
Dynamic Programming Find if a string is interleaved of two other strings
Dynamic Programming Maximum Length of Pair Chain
Bit Manipulation Count set bits in an integer
Bit Manipulation Find the two non-repeating elements in an array of repeating elements
Bit Manipulation Count number of bits to be flipped to convert A to B
Bit Manipulation Count total set bits in all numbers from 1 to n
Bit Manipulation Program to find whether a no is power of two
Bit Manipulation Find position of the only set bit
Bit Manipulation Copy set bits in a range
Bit Manipulation Divide two integers without using multiplication, division and mod operator
Bit Manipulation Calculate square of a number without using *, / and pow()
Bit Manipulation Power Set

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