DSA Sheet by Love Babbar
Love Babbar is a famous Youtuber, a graduate from NSUT Delhi who has also worked as a Software Engineer in Amazon.
A sheet that covers almost every concept of Data Structures and Algorithms.
So, this DSA sheet by Love Babbar contains 450 coding questions which will help in:
- Understanding each and every concept of DSA.
- Clearing the DSA round for the Interviews, as these are the questions generally asked in the companies like Amazon, Microsoft, Google, etc.
- Pre-requisites for DSA sheet:
- Basic Knowledge of Data Structures and Algorithms.
- Having good knowledge of at-least one programming knowledge like C++, Java, Python.
- Know how to use STL as it will make data structures and few techniques easier to implement.
Below is the topic-wise distribution of 450 questions:
This sheet can be completed within 2-3 months without any cheat day.
So, Start solving this 450 DSA Cracker from today itself.
Keep a track of all the problems mentioned below: Practice Love Babbar DSA Sheet
Question Article Practice Reverse the array Link Link Find the maximum and minimum element in an array Link Link Find the “Kth” max and min element of an array Link Link Given an array which consists of only 0, 1 and 2. Sort the array without using any sorting algo Link Link Move all the negative elements to one side of the array Link Link Find the Union and Intersection of the two sorted arrays. Link Link Write a program to cyclically rotate an array by one. Link Link Find Largest sum contiguous Subarray [V. IMP] Link Link Minimize the maximum difference between heights [V.IMP] Link Link Minimum no. of Jumps to reach end of an array Link Link Find duplicate in an array of N+1 Integers Link Link Merge 2 sorted arrays without using Extra space. Link Link Kadane’s Algo [V.V.V.V.V IMP] Link Link Merge Intervals Link Link Next Permutation Link Link Count Inversion Link Link Best time to buy and Sell stock Link Link Find all pairs on integer array whose sum is equal to given number Link Link Find common elements In 3 sorted arrays Link Link Rearrange the array in alternating positive and negative items with O(1) extra space Link Link Find if there is any subarray with sum equal to 0 Link Link Find factorial of a large number Link Link Find maximum product subarray Link Link Find longest consecutive subsequence Link Link Given an array of size n and a number k, fin all elements that appear more than ” n/k ” times. Link NA Maximum profit by buying and selling a share at most twice Link Link Find whether an array is a subset of another array Link Link Find the triplet that sum to a given value Link Link Trapping Rain water problem Link Link Chocolate Distribution problem Link Link Smallest Subarray with sum greater than a given value Link Link Three way partitioning of an array around a given value Link Link Minimum swaps required bring elements less equal K together Link Link Minimum no. of operations required to make an array palindrome Link Link Median of 2 sorted arrays of equal size Link Link Median of 2 sorted arrays of different size Link Link
Question Article Practice Spiral traversal on a Matrix Link LInk Search an element in a Matrix Link Link Find median in a row wise sorted matrix Link Link Find row with maximum no. of 1’s Link Link Print elements in sorted order using row-column wise sorted matrix Link Link Maximum size rectangle Link Link Find a specific pair in matrix Link NA Rotate matrix by 90 degrees Link Link Kth smallest element in a row-column wise sorted matrix Link Link Common elements in all rows of a given matrix Link Link
Question Article Practice Reverse a String Link Link Check whether a String is Palindrome or not Link Link Find Duplicate characters in a string Link NA Why strings are immutable in Java? Link NA Write a Code to check whether one string is a rotation of another Link Link Write a Program to check whether a string is a valid shuffle of two strings or not Link NA Count and Say problem Link Link Write a program to find the longest Palindrome in a string.[ Longest palindromic Substring] Link Link Find Longest Recurring Subsequence in String Link Link Print all Subsequences of a string. Link NA Print all the permutations of the given string Link Link Split the Binary string into two substring with equal 0’s and 1’s Link NA Word Wrap Problem [VERY IMP]. Link Link EDIT Distance [Very Imp] Link Link Find next greater number with same set of digits. [Very Very IMP] Link Link Balanced Parenthesis problem.[Imp] Link Link Word break Problem[ Very Imp] Link Link Rabin Karp Algorithm Link Link KMP Algorithm Link Link Convert a Sentence into its equivalent mobile numeric keypad sequence. Link Link Minimum number of bracket reversals needed to make an expression balanced. Link Link Count All Palindromic Subsequence in a given String. Link Link Count of number of given string in 2D character array Link Link Search a Word in a 2D Grid of characters. Link Link Boyer Moore Algorithm for Pattern Searching. Link Link Converting Roman Numerals to Decimal Link Link Longest Common Prefix Link Link Number of flips to make binary string alternate Link Link Find the first repeated word in string. Link Link Minimum number of swaps for bracket balancing. Link Link Find the longest common subsequence between two strings. Link Link Program to generate all possible valid IP addresses from given string. Link Link Write a program to find the smallest window that contains all characters of string itself. Link Link Rearrange characters in a string such that no two adjacent are same Link Link Minimum characters to be added at front to make string palindrome Link Link Given a sequence of words, print all anagrams together Link Link Find the smallest window in a string containing all characters of another string Link Link Recursively remove all adjacent duplicates Link Link String matching where one string contains wildcard characters Link Link Function to find Number of customers who could not get a computer Link NA Transform One String to Another using Minimum Number of Given Operation Link Link Check if two given strings are isomorphic to each other Link Link Recursively print all sentences that can be formed from list of word lists Link NA
Searching and Sorting:
Question Article Practice Find first and last positions of an element in a sorted array Link Link Find a Fixed Point (Value equal to index) in a given array Link Link Search in a rotated sorted array Link Link Square root of an integer Link Link Maximum and minimum of an array using minimum number of comparisons Link Link Optimum location of point to minimize total distance Link Link Find the repeating and the missing Link Link Find majority element Link Link Searching in an array where adjacent differ by at most k Link Link Find a pair with a given difference Link Link Find four elements that sum to a given value Link Link Maximum sum such that no 2 elements are adjacent Link Link Count triplet with sum smaller than a given value Link Link Merge 2 sorted arrays Link Link Product array Puzzle Link Link Sort array according to count of set bits Link Link Minimum no. of swaps required to sort the array Link Link Bishu and Soldiers Link Link Rasta and Kheshtak Link Link Kth smallest number again Link Link Find pivot element in a sorted array Link Link K-th Element of Two Sorted Arrays Link Link Aggressive cows Link Link Book Allocation Problem Link Link EKOSPOJ: Link Link Job Scheduling Algo Link Link Missing Number in AP Link Link Smallest number with atleast n trailing zeroes in factorial Link Link Painters Partition Problem: Link Link ROTI-Prata SPOJ Link Link DoubleHelix SPOJ Link Link Subset Sums Link Link Find the inversion count Link Link Implement Merge-sort in-place Link Link Partitioning and Sorting Arrays with Many Repeated Entries Link Link
Question Article Practice Write a Program to reverse the Linked List. (Both Iterative and recursive) Link Link Reverse a Linked List in group of Given Size. [Very Imp] Link Link Write a program to Detect loop in a linked list. Link Link Write a program to Delete loop in a linked list. Link Link Find the starting point of the loop. Link Link Remove Duplicates in a sorted Linked List. Link Link Remove Duplicates in a Un-sorted Linked List. Link Link Write a Program to Move the last element to Front in a Linked List. Link Link Add “1” to a number represented as a Linked List. Link Link Add two numbers represented by linked lists. Link Link Intersection of two Sorted Linked List. Link Link Intersection Point of two Linked Lists. Link Link Merge Sort For Linked lists.[Very Important] Link Link Quicksort for Linked Lists.[Very Important] Link Link Find the middle Element of a linked list. Link Link Check if a linked list is a circular linked list. Link Link Split a Circular linked list into two halves. Link Link Write a Program to check whether the Singly Linked list is a palindrome or not. Link Link Deletion from a Circular Linked List. Link Link Reverse a Doubly Linked list. Link Link Find pairs with a given sum in a DLL. Link Link Count triplets in a sorted DLL whose sum is equal to given value “X”. Link Link Sort a “k”sorted Doubly Linked list.[Very IMP] Link Link Rotate Doubly Linked list by N nodes. Link Link Rotate a Doubly Linked list in group of Given Size.[Very IMP] Link Link Can we reverse a linked list in less than O(n) ? Link Link Why Quicksort is preferred for. Arrays and Merge Sort for Linked Lists ? Link Link Flatten a Linked List Link Link Sort a LL of 0’s, 1’s and 2’s Link Link Clone a linked list with next and random pointer Link Link Merge K sorted Linked list Link Link Multiply 2 no. represented by LL Link Link Delete nodes which have a greater value on right side Link Link Segregate even and odd nodes in a Linked List Link Link Program for n’th node from the end of a Linked List Link Link
Question Article Practice Count set bits in an integer Link Link Find the two non-repeating elements in an array of repeating elements Link Link Count number of bits to be flipped to convert A to B Link Link Count total set bits in all numbers from 1 to n Link Link Program to find whether a no is power of two Link Link Find position of the only set bit Link Link Copy set bits in a range Link Link Divide two integers without using multiplication, division and mod operator Link Link Calculate square of a number without using *, / and pow() Link Link Power Set Link Link
Question Article Practice Activity Selection Problem Link Link Job Sequencing Problem Link Link Huffman Coding Link Link Water Connection Problem Link Link Fractional Knapsack Problem Link Link Greedy Algorithm to find Minimum number of Coins Link Link Maximum trains for which stoppage can be provided Link Link Minimum Platforms Problem Link Link Buy Maximum Stocks if i stocks can be bought on i-th day Link Link Find the minimum and maximum amount to buy all N candies Link Link Minimize Cash Flow among a given set of friends who have borrowed money from each other Link Link Minimum Cost to cut a board into squares Link Link Check if it is possible to survive on Island Link Link Find maximum meetings in one room Link Link Maximum product subset of an array Link Link Maximize array sum after K negations Link Link Maximize the sum of arr[i]*i Link Link Maximum sum of absolute difference of an array Link Link Maximize sum of consecutive differences in a circular array Link Link Minimum sum of absolute difference of pairs of two arrays Link Link Program for Shortest Job First (or SJF) CPU Scheduling Link Link Program for Least Recently Used (LRU) Page Replacement algorithm Link Link Smallest subset with sum greater than all other elements Link Link Chocolate Distribution Problem Link Link DEFKIN -Defense of a Kingdom Link Link DIEHARD -DIE HARD Link Link GERGOVIA -Wine trading in Gergovia Link Link Picking Up Chicks Link Link CHOCOLA –Chocolate Link Link ARRANGE -Arranging Amplifiers Link Link K Centers Problem Link Link Minimum Cost of ropes Link Link Find smallest number with given number of digits and sum of digits Link Link Rearrange characters in a string such that no two adjacent are same Link Link Find maximum sum possible equal sum of three stacks Link Link
Question Article Practice Rat in a maze Problem Link Link Printing all solutions in N-Queen Link Link Word Break Problem using Backtracking Link Link Remove Invalid Parentheses Link Link Sudoku Solver Link Link M Coloring Problem Link Link Print all palindromic partitions of a string Link Link Subset Sum Problem Link Link The Knight’s tour problem Link Link Tug of War Link Link Find shortest safe route in a path with landmines Link Link Combinational Sum Link Link Find Maximum number possible by doing at-most K swaps Link Link Print all permutations of a string Link Link Find if there is a path of more than k length from a source Link Link Longest Possible Route in a Matrix with Hurdles Link Link Print all possible paths from top left to bottom right of a mXn matrix Link Link Partition of a set into K subsets with equal sum Link Link Find the K-th Permutation Sequence of first N natural numbers Link Link
Question Article Practice Coin Change Problem Link Link Knapsack Problem Link Link Binomial Coefficient Problem Link Link Permutation Coefficient Problem Link Link Program for nth Catalan Number Link Link Matrix Chain Multiplication Link Link Edit Distance Link Link Subset Sum Problem Link Link Friends Pairing Problem Link Link Gold Mine Problem Link Link Assembly Line Scheduling Problem Link Link Painting the Fence problem Link Link Maximize The Cut Segments Link Link Longest Common Subsequence Link Link Longest Repeated Subsequence Link Link Longest Increasing Subsequence Link Link Space Optimized Solution of LCS Link Link LCS (Longest Common Subsequence) of three strings Link Link Maximum Sum Increasing Subsequence Link Link Count all subsequences having product less than K Link Link Longest subsequence such that difference between adjacent is one Link Link Maximum subsequence sum such that no three are consecutive Link Link Egg Dropping Problem Link Link Maximum Length Chain of Pairs Link Link Maximum size square sub-matrix with all 1s Link Link Maximum sum of pairs with specific difference Link Link Min Cost Path Problem Link Link Maximum difference of zeros and ones in binary string Link Link Minimum number of jumps to reach end Link Link Minimum cost to fill given weight in a bag Link Link Minimum removals from array to make max –min <= K Link Link Longest Common Substring Link Link Count number of ways to reach a given score in a game Link Link Count Balanced Binary Trees of Height h Link Link LargestSum Contiguous Subarray [V>V>V>V IMP ] Link Link Smallest sum contiguous subarray Link Link Unbounded Knapsack (Repetition of items allowed) Link Link Word Break Problem Link Link Largest Independent Set Problem Link Link Partition problem Link Link Longest Palindromic Subsequence Link Link Count All Palindromic Subsequence in a given String Link Link Longest Palindromic Substring Link Link Longest alternating subsequence Link Link Weighted Job Scheduling Link Link Coin game winner where every player has three choices Link Link Count Derangements (Permutation such that no element appears in its original position) [ IMPORTANT ] Link Link Maximum profit by buying and selling a share at most twice [ IMP ] Link Link Optimal Strategy for a Game Link Link Optimal Binary Search Tree Link Link Palindrome Partitioning Problem Link Link Word Wrap Problem Link Link Mobile Numeric Keypad Problem [ IMP ] Link Link Boolean Parenthesization Problem Link Link Largest rectangular sub-matrix whose sum is 0 Link Link Largest area rectangular sub-matrix with equal number of 1’s and 0’s [ IMP ] Link Link Maximum sum rectangle in a 2D matrix Link Link Maximum profit by buying and selling a share at most k times Link Link Find if a string is interleaved of two other strings Link Link Maximum Length of Pair Chain Link Link
Stacks and Queues:
Question Article Practice Implement Stack from Scratch Link Link Implement Queue from Scratch Link Link Implement 2 stack in an array Link Link Find the middle element of a stack Link Link Implement “N” stacks in an Array Link Link Check the expression has valid or Balanced parenthesis or not. Link Link Reverse a String using Stack Link Link Design a Stack that supports getMin() in O(1) time and O(1) extra space. Link Link Find the next Greater element Link Link The celebrity Problem Link Link Arithmetic Expression evaluation Link Link Evaluation of Postfix expression Link Link Implement a method to insert an element at its bottom without using any other data structure. Link Link Reverse a stack using recursion Link Link Sort a Stack using recursion Link Link Merge Overlapping Intervals Link Link Largest rectangular Area in Histogram Link Link Length of the Longest Valid Substring Link Link Expression contains redundant bracket or not Link Link Implement Stack using Queue Link Link Implement Stack using Deque Link Link Stack Permutations (Check if an array is stack permutation of other) Link Link Implement Queue using Stack Link Link Implement “n” queue in an array Link Link Implement a Circular queue Link Link LRU Cache Implementation Link Link Reverse a Queue using recursion Link Link Reverse the first “K” elements of a queue Link Link Interleave the first half of the queue with second half Link Link Find the first circular tour that visits all Petrol Pumps Link Link Minimum time required to rot all oranges Link Link Distance of nearest cell having 1 in a binary matrix Link Link First negative integer in every window of size “k” Link Link Check if all levels of two trees are anagrams or not. Link Link Sum of minimum and maximum elements of all subarrays of size “k”. Link Link Minimum sum of squares of character counts in a given string after removing “k” characters. Link Link Queue based approach or first non-repeating character in a stream. Link Link Next Smaller Element Link Link
Question Article Practice Level order traversal Link Link Reverse Level Order traversal Link Link Height of a tree Link Link Diameter of a tree Link Link Mirror of a tree Link Link Inorder Traversal of a tree both using recursion and Iteration Link Link Preorder Traversal of a tree both using recursion and Iteration Link Link Postorder Traversal of a tree both using recursion and Iteration Link Link Left View of a tree Link Link Right View of Tree Link Link Top View of a tree Link Link Bottom View of a tree Link Link Zig-Zag traversal of a binary tree Link Link Check if a tree is balanced or not Link Link Diagonal Traversal of a Binary tree Link Link Boundary traversal of a Binary tree Link Link Construct Binary Tree from String with Bracket Representation Link Link Convert Binary tree into Doubly Linked List Link Link Convert Binary tree into Sum tree Link Link Construct Binary tree from Inorder and preorder traversal Link Link Find minimum swaps required to convert a Binary tree into BST Link Link Check if Binary tree is Sum tree or not Link Link Check if all leaf nodes are at same level or not Link Link Check if a Binary Tree contains duplicate subtrees of size 2 or more [ IMP ] Link Link Check if 2 trees are mirror or not Link Link Sum of Nodes on the Longest path from root to leaf node Link Link Check if given graph is tree or not. [ IMP ] Link Link Find Largest subtree sum in a tree Link Link Maximum Sum of nodes in Binary tree such that no two are adjacent Link Link Print all “K” Sum paths in a Binary tree Link Link Find LCA in a Binary tree Link Link Find distance between 2 nodes in a Binary tree Link Link Kth Ancestor of node in a Binary tree Link Link Find all Duplicate subtrees in a Binary tree [ IMP ] Link Link Tree Isomorphism Problem Link Link
Binary Search Tree:
Question Article Practice Find a value in a BST Link Link Deletion of a node in a BST Link Link Find min and max value in a BST Link Link Find inorder successor and inorder predecessor in a BST Link Link Check if a tree is a BST or not Link Link Populate Inorder successor of all nodes Link Link Find LCA of 2 nodes in a BST Link Link Construct BST from preorder traversal Link Link Convert Binary tree into BST Link Link Convert a normal BST into a Balanced BST Link Link Merge two BST [ V.V.V>IMP ] Link Link Find Kth largest element in a BST Link Link Find Kth smallest element in a BST Link Link Count pairs from 2 BST whose sum is equal to given value “X” Link Link Find the median of BST in O(n) time and O(1) space Link Link Count BST nodes that lie in a given range Link Link Replace every element with the least greater element on its right Link Link Given “n” appointments, find the conflicting appointments Link Link Check preorder is valid or not Link Link Check whether BST contains Dead end Link Link Largest BST in a Binary Tree [ V.V.V.V.V IMP ] Link Link Flatten BST to sorted list Link Link
Question Article Practice Create a Graph, print it Link Link Implement BFS algorithm Link Link Implement DFS Algo Link Link Detect Cycle in Directed Graph using BFS/DFS Algo Link Link Detect Cycle in UnDirected Graph using BFS/DFS Algo Link Link Search in a Maze Link Link Minimum Step by Knight Link Link Flood fill algo Link Link Clone a graph Link Link Making wired Connections Link Link Word Ladder Link Link Dijkstra algo Link Link Implement Topological Sort Link Link Minimum time taken by each job to be completed given by a Directed Acyclic Graph Link Link Find whether it is possible to finish all tasks or not from given dependencies Link Link Find the no. of Islands Link Link Given a sorted Dictionary of an Alien Language, find order of characters Link Link Implement Kruksal’sAlgorithm Link Link Implement Prim’s Algorithm Link Link Total no. of Spanning tree in a graph Link Link Implement Bellman Ford Algorithm Link Link Implement Floyd warshall Algorithm Link Link Travelling Salesman Problem Link Link Graph Colouring Problem Link Link Snake and Ladders Problem Link Link Find bridge in a graph Link Link Count Strongly connected Components(Kosaraju Algo) Link Link Check whether a graph is Bipartite or Not Link Link Detect Negative cycle in a graph Link Link Longest path in a Directed Acyclic Graph Link Link Journey to the Moon Link Link Cheapest Flights Within K Stops Link Link Oliver and the Game Link Link Water Jug problem using BFS Link Link Find if there is a path of more thank length from a source Link Link M-Colouring Problem Link Link Minimum edges to reverse to make path from source to destination Link Link Paths to travel each nodes using each edge(Seven Bridges) Link Link Vertex Cover Problem Link Link Chinese Postman or Route Inspection Link Link Number of Triangles in a Directed and Undirected Graph Link Link Minimise the cashflow among a given set of friends who have borrowed money from each other Link Link Two Clique Problem Link Link
Question Article Practice Implement a Maxheap/MinHeap using arrays and recursion. Link Link Sort an Array using heap. (HeapSort) Link Link Maximum of all subarrays of size k. Link Link “K” largest element in an array Link Link Kth smallest and largest element in an unsorted array Link Link Merge “K” sorted arrays. [ IMP ] Link Link Merge 2 Binary Max Heaps Link Link Kth largest sum continuous subarrays Link Link Leetcode- reorganize strings Link Link Merge “K” Sorted Linked Lists [V.IMP] Link Link Smallest range in “K” Lists Link Link Median in a stream of Integers Link Link Check if a Binary Tree is Heap Link Link Connect “n” ropes with minimum cost Link Link Convert BST to Min Heap Link Link Convert min heap to max heap Link Link Rearrange characters in a string such that no two adjacent are same. Link Link Minimum sum of two numbers formed from digits of an array Link Link
Question Article Practice Construct a trie from scratch Link Link Find shortest unique prefix for every word in a given list Link Link Word Break Problem | (Trie solution) Link Link Given a sequence of words, print all anagrams together Link Link Implement a Phone Directory Link Link Print unique rows in a given boolean matrix Link Link
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CODE to DSA 😎