DSA Practice Checklist — CrackThePrep

Array 0/36

Reverse the array◆ solutions
Find the maximum and minimum element in an array◆ solutions
Find the "Kth" max and min element of an array◆ solutions
Given an array which consists of only 0, 1 and 2. Sort the array without using any sorting algo◆ solutions
Move all the negative elements to one side of the array◆ solutions
Find the Union and Intersection of the two sorted arrays◆ solutions
Write a program to cyclically rotate an array by one◆ solutions
find Largest sum contiguous Subarray ★◆ solutions
Minimise the maximum difference between heights ★◆ solutions
Minimum no. of Jumps to reach end of an array◆ solutions
find duplicate in an array of N+1 Integers◆ solutions
Merge 2 sorted arrays without using Extra space◆ solutions
Kadane's Algo ★◆ solutions
Merge Intervals◆ solutions
Next Permutation◆ solutions
Count Inversion◆ solutions
Best time to buy and Sell stock◆ solutions
find all pairs on integer array whose sum is equal to given number◆ solutions
find common elements In 3 sorted arrays◆ solutions
Rearrange the array in alternating positive and negative items with O(1) extra space◆ solutions
Find if there is any subarray with sum equal to 0◆ solutions
Find factorial of a large number◆ solutions
find maximum product subarray◆ solutions
Find longest coinsecutive subsequence◆ solutions
Given an array of size n and a number k, fin all elements that appear more than " n/k " times◆ solutions
Maximum profit by buying and selling a share atmost twice◆ solutions
Find whether an array is a subset of another array◆ solutions
Find the triplet that sum to a given value◆ solutions
Trapping Rain water problem◆ solutions
Chocolate Distribution problem◆ solutions
Smallest Subarray with sum greater than a given value◆ solutions
Three way partitioning of an array around a given value◆ solutions
Minimum swaps required bring elements less equal K together◆ solutions
Minimum no. of operations required to make an array palindrome◆ solutions
Median of 2 sorted arrays of equal size◆ solutions
Median of 2 sorted arrays of different size◆ solutions

Matrix 0/10

Spiral traversal on a Matrix◆ solutions
Search an element in a matriix◆ solutions
Find median in a row wise sorted matrix◆ solutions
Find row with maximum no. of 1's◆ solutions
Print elements in sorted order using row-column wise sorted matrix◆ solutions
Maximum size rectangle◆ solutions
Find a specific pair in matrix◆ solutions
Rotate matrix by 90 degrees◆ solutions
Kth smallest element in a row-cpumn wise sorted matrix◆ solutions
Common elements in all rows of a given matrix◆ solutions

String 0/42

Reverse a String◆ solutions
Check whether a String is Palindrome or not◆ solutions
Find Duplicate characters in a string◆ solutions
Write a Code to check whether one string is a rotation of another◆ solutions
Write a Program to check whether a string is a valid shuffle of two strings or not◆ solutions
Count and Say problem◆ solutions
Write a program to find the longest Palindrome in a string◆ solutions
Find Longest Recurring Subsequence in String◆ solutions
Print all Subsequences of a string◆ solutions
Print all the permutations of the given string◆ solutions
Split the Binary string into two substring with equal 0’s and 1’s◆ solutions
Word Wrap Problem [VERY IMP] ★◆ solutions
EDIT Distance ★◆ solutions
Find next greater number with same set of digits ★◆ solutions
Balanced Parenthesis problem ★◆ solutions
Word break Problem ★◆ solutions
Rabin Karp Algo◆ solutions
KMP Algo◆ solutions
Convert a Sentence into its equivalent mobile numeric keypad sequence◆ solutions
Minimum number of bracket reversals needed to make an expression balanced◆ solutions
Count All Palindromic Subsequence in a given String◆ solutions
Count of number of given string in 2D character array◆ solutions
Search a Word in a 2D Grid of characters◆ solutions
Boyer Moore Algorithm for Pattern Searching◆ solutions
Converting Roman Numerals to Decimal◆ solutions
Longest Common Prefix◆ solutions
Number of flips to make binary string alternate◆ solutions
Find the first repeated word in string◆ solutions
Minimum number of swaps for bracket balancing◆ solutions
Find the longest common subsequence between two strings◆ solutions
Program to generate all possible valid IP addresses from given string◆ solutions
Write a program tofind the smallest window that contains all characters of string itself◆ solutions
Rearrange characters in a string such that no two adjacent are same◆ solutions
Minimum characters to be added at front to make string palindrome◆ solutions
Given a sequence of words, print all anagrams together◆ solutions
Find the smallest window in a string containing all characters of another string◆ solutions
Recursively remove all adjacent duplicates◆ solutions
String matching where one string contains wildcard characters◆ solutions
Function to find Number of customers who could not get a computer◆ solutions
Transform One String to Another using Minimum Number of Given Operation◆ solutions
Check if two given strings are isomorphic to each other◆ solutions
Recursively print all sentences that can be formed from list of word lists◆ solutions

Searching & Sorting 0/36

Find first and last positions of an element in a sorted array◆ solutions
Find a Fixed Point (Value equal to index) in a given array◆ solutions
Search in a rotated sorted array◆ solutions
square root of an integer◆ solutions
Maximum and minimum of an array using minimum number of comparisons◆ solutions
Optimum location of point to minimize total distance◆ solutions
Find the repeating and the missing◆ solutions
find majority element◆ solutions
Searching in an array where adjacent differ by at most k◆ solutions
find a pair with a given difference◆ solutions
find four elements that sum to a given value◆ solutions
maximum sum such that no 2 elements are adjacent◆ solutions
Count triplet with sum smaller than a given value◆ solutions
merge 2 sorted arrays◆ solutions
print all subarrays with 0 sum◆ solutions
Product array Puzzle◆ solutions
Sort array according to count of set bits◆ solutions
minimum no. of swaps required to sort the array◆ solutions
Bishu and Soldiers◆ solutions
Rasta and Kheshtak◆ solutions
Kth smallest number again◆ solutions
Find pivot element in a sorted array◆ solutions
K-th Element of Two Sorted Arrays◆ solutions
Aggressive cows◆ solutions
Book Allocation Problem◆ solutions
EKOSPOJ:◆ solutions
Job Scheduling Algo◆ solutions
Missing Number in AP◆ solutions
Smallest number with atleastn trailing zeroes infactorial◆ solutions
Painters Partition Problem:◆ solutions
ROTI-Prata SPOJ◆ solutions
DoubleHelix SPOJ◆ solutions
Subset Sums◆ solutions
Findthe inversion count◆ solutions
Implement Merge-sort in-place◆ solutions
Partitioning and Sorting Arrays with Many Repeated Entries◆ solutions

LinkedList 0/36

Write a Program to reverse the Linked List. (Both Iterative and recursive)◆ solutions
Reverse a Linked List in group of Given Size ★◆ solutions
Write a program to Detect loop in a linked list◆ solutions
Write a program to Delete loop in a linked list◆ solutions
Find the starting point of the loop◆ solutions
Remove Duplicates in a sorted Linked List◆ solutions
Remove Duplicates in a Un-sorted Linked List◆ solutions
Write a Program to Move the last element to Front in a Linked List◆ solutions
Add “1” to a number represented as a Linked List◆ solutions
Add two numbers represented by linked lists◆ solutions
Intersection of two Sorted Linked List◆ solutions
Intersection Point of two Linked Lists◆ solutions
Merge Sort For Linked lists ★◆ solutions
Quicksort for Linked Lists ★◆ solutions
Find the middle Element of a linked list◆ solutions
Check if a linked list is a circular linked list◆ solutions
Split a Circular linked list into two halves◆ solutions
Write a Program to check whether the Singly Linked list is a palindrome or not◆ solutions
Deletion from a Circular Linked List◆ solutions
Reverse a Doubly Linked list◆ solutions
Find pairs with a given sum in a DLL◆ solutions
Count triplets in a sorted DLL whose sum is equal to given value “X”◆ solutions
Sort a “k”sorted Doubly Linked list ★◆ solutions
Rotate DoublyLinked list by N nodes◆ solutions
Rotate a Doubly Linked list in group of Given Size ★◆ solutions
Can we reverse a linked list in less than O(n) ?◆ solutions
Why Quicksort is preferred for. Arrays and Merge Sort for LinkedLists ?◆ solutions
Flatten a Linked List◆ solutions
Sort a LL of 0's, 1's and 2's◆ solutions
Clone a linked list with next and random pointer◆ solutions
Merge K sorted Linked list◆ solutions
Multiply 2 no. represented by LL◆ solutions
Delete nodes which have a greater value on right side◆ solutions
Segregate even and odd nodes in a Linked List◆ solutions
Program for n’th node from the end of a Linked List◆ solutions
Find the first non-repeating character from a stream of characters◆ solutions

Binary Trees 0/35

level order traversal◆ solutions
Reverse Level Order traversal◆ solutions
Height of a tree◆ solutions
Diameter of a tree◆ solutions
Mirror of a tree◆ solutions
Inorder Traversal of a tree both using recursion and Iteration◆ solutions
Preorder Traversal of a tree both using recursion and Iteration◆ solutions
Postorder Traversal of a tree both using recursion and Iteration◆ solutions
Left View of a tree◆ solutions
Right View of Tree◆ solutions
Top View of a tree◆ solutions
Bottom View of a tree◆ solutions
Zig-Zag traversal of a binary tree◆ solutions
Check if a tree is balanced or not◆ solutions
Diagnol Traversal of a Binary tree◆ solutions
Boundary traversal of a Binary tree◆ solutions
Construct Binary Tree from String with Bracket Representation◆ solutions
Convert Binary tree into Doubly Linked List◆ solutions
Convert Binary tree into Sum tree◆ solutions
Construct Binary tree from Inorder and preorder traversal◆ solutions
Find minimum swaps required to convert a Binary tree into BST◆ solutions
Check if Binary tree is Sum tree or not◆ solutions
Check if all leaf nodes are at same level or not◆ solutions
Check if a Binary Tree contains duplicate subtrees of size 2 or more ★◆ solutions
Check if 2 trees are mirror or not◆ solutions
Sum of Nodes on the Longest path from root to leaf node◆ solutions
Check if given graph is tree or not ★◆ solutions
Find Largest subtree sum in a tree◆ solutions
Maximum Sum of nodes in Binary tree such that no two are adjacent◆ solutions
Print all "K" Sum paths in a Binary tree◆ solutions
Find LCA in a Binary tree◆ solutions
Find distance between 2 nodes in a Binary tree◆ solutions
Kth Ancestor of node in a Binary tree◆ solutions
Find all Duplicate subtrees in a Binary tree ★◆ solutions
Tree Isomorphism Problem◆ solutions

Binary Search Trees 0/22

Fina a value in a BST◆ solutions
Deletion of a node in a BST◆ solutions
Find min and max value in a BST◆ solutions
Find inorder successor and inorder predecessor in a BST◆ solutions
Check if a tree is a BST or not◆ solutions
Populate Inorder successor of all nodes◆ solutions
Find LCA of 2 nodes in a BST◆ solutions
Construct BST from preorder traversal◆ solutions
Convert Binary tree into BST◆ solutions
Convert a normal BST into a Balanced BST◆ solutions
Merge two BST ★◆ solutions
Find Kth largest element in a BST◆ solutions
Find Kth smallest element in a BST◆ solutions
Count pairs from 2 BST whose sum is equal to given value "X"◆ solutions
Find the median of BST in O(n) time and O(1) space◆ solutions
Count BST ndoes that lie in a given range◆ solutions
Replace every element with the least greater element on its right◆ solutions
Given "n" appointments, find the conflicting appointments◆ solutions
Check preorder is valid or not◆ solutions
Check whether BST contains Dead end◆ solutions
Largest BST in a Binary Tree ★◆ solutions
Flatten BST to sorted list◆ solutions

Greedy 0/35

Activity Selection Problem◆ solutions
Job SequencingProblem◆ solutions
Huffman Coding◆ solutions
Water Connection Problem◆ solutions
Fractional Knapsack Problem◆ solutions
Greedy Algorithm to find Minimum number of Coins◆ solutions
Maximum trains for which stoppage can be provided◆ solutions
Minimum Platforms Problem◆ solutions
Buy Maximum Stocks if i stocks can be bought on i-th day◆ solutions
Find the minimum and maximum amount to buy all N candies◆ solutions
Minimize Cash Flow among a given set of friends who have borrowed money from each other◆ solutions
Minimum Cost to cut a board into squares◆ solutions
Check if it is possible to survive on Island◆ solutions
Find maximum meetings in one room◆ solutions
Maximum product subset of an array◆ solutions
Maximize array sum after K negations◆ solutions
Maximize the sum of arr[i]*i◆ solutions
Maximum sum of absolute difference of an array◆ solutions
Maximize sum of consecutive differences in a circular array◆ solutions
Minimum sum of absolute difference of pairs of two arrays◆ solutions
Program for Shortest Job First (or SJF) CPU Scheduling◆ solutions
Program for Least Recently Used (LRU) Page Replacement algorithm◆ solutions
Smallest subset with sum greater than all other elements◆ solutions
Chocolate Distribution Problem◆ solutions
DEFKIN -Defense of a Kingdom◆ solutions
DIEHARD -DIE HARD◆ solutions
GERGOVIA -Wine trading in Gergovia◆ solutions
Picking Up Chicks◆ solutions
CHOCOLA –Chocolate◆ solutions
ARRANGE -Arranging Amplifiers◆ solutions
K Centers Problem◆ solutions
Minimum Cost of ropes◆ solutions
Find smallest number with given number of digits and sum of digits◆ solutions
Rearrange characters in a string such that no two adjacent are same◆ solutions
Find maximum sum possible equal sum of three stacks◆ solutions

BackTracking 0/19

Rat in a maze Problem◆ solutions
Printing all solutions in N-Queen Problem◆ solutions
Word Break Problem using Backtracking◆ solutions
Remove Invalid Parentheses◆ solutions
Sudoku Solver◆ solutions
m Coloring Problem◆ solutions
Print all palindromic partitions of a string◆ solutions
Subset Sum Problem◆ solutions
The Knight’s tour problem◆ solutions
Tug of War◆ solutions
Find shortest safe route in a path with landmines◆ solutions
Combinational Sum◆ solutions
Find Maximum number possible by doing at-most K swaps◆ solutions
Print all permutations of a string◆ solutions
Find if there is a path of more than k length from a source◆ solutions
Longest Possible Route in a Matrix with Hurdles◆ solutions
Print all possible paths from top left to bottom right of a mXn matrix◆ solutions
Partition of a set intoK subsets with equal sum◆ solutions
Find the K-th Permutation Sequence of first N natural numbers◆ solutions

Stacks & Queues 0/38

Implement Stack from Scratch◆ solutions
Implement Queue from Scratch◆ solutions
Implement 2 stack in an array◆ solutions
find the middle element of a stack◆ solutions
Implement "N" stacks in an Array◆ solutions
Check the expression has valid or Balanced parenthesis or not◆ solutions
Reverse a String using Stack◆ solutions
Design a Stack that supports getMin() in O(1) time and O(1) extra space◆ solutions
Find the next Greater element◆ solutions
The celebrity Problem◆ solutions
Arithmetic Expression evaluation◆ solutions
Evaluation of Postfix expression◆ solutions
Implement a method to insert an element at its bottom without using any other data structure◆ solutions
Reverse a stack using recursion◆ solutions
Sort a Stack using recursion◆ solutions
Merge Overlapping Intervals◆ solutions
Largest rectangular Area in Histogram◆ solutions
Length of the Longest Valid Substring◆ solutions
Expression contains redundant bracket or not◆ solutions
Implement Stack using Queue◆ solutions
Implement Stack using Deque◆ solutions
Stack Permutations (Check if an array is stack permutation of other)◆ solutions
Implement Queue using Stack◆ solutions
Implement "n" queue in an array◆ solutions
Implement a Circular queue◆ solutions
LRU Cache Implementationa◆ solutions
Reverse a Queue using recursion◆ solutions
Reverse the first “K” elements of a queue◆ solutions
Interleave the first half of the queue with second half◆ solutions
Find the first circular tour that visits all Petrol Pumps◆ solutions
Minimum time required to rot all oranges◆ solutions
Distance of nearest cell having 1 in a binary matrix◆ solutions
First negative integer in every window of size “k”◆ solutions
Check if all levels of two trees are anagrams or not◆ solutions
Sum of minimum and maximum elements of all subarrays of size “k”◆ solutions
Minimum sum of squares of character counts in a given string after removing “k” characters◆ solutions
Queue based approach or first non-repeating character in a stream◆ solutions
Next Smaller Element◆ solutions

Heap 0/18

Implement a Maxheap/MinHeap using arrays and recursion◆ solutions
Sort an Array using heap. (HeapSort)◆ solutions
Maximum of all subarrays of size k◆ solutions
“k” largest element in an array◆ solutions
Kth smallest and largest element in an unsorted array◆ solutions
Merge “K” sorted arrays ★◆ solutions
Merge 2 Binary Max Heaps◆ solutions
Kth largest sum continuous subarrays◆ solutions
Leetcode- reorganize strings◆ solutions
Merge “K” Sorted Linked Lists ★◆ solutions
Smallest range in “K” Lists◆ solutions
Median in a stream of Integers◆ solutions
Check if a Binary Tree is Heap◆ solutions
Connect “n” ropes with minimum cost◆ solutions
Convert BST to Min Heap◆ solutions
Convert min heap to max heap◆ solutions
Rearrange characters in a string such that no two adjacent are same◆ solutions
Minimum sum of two numbers formed from digits of an array◆ solutions

Graph 0/44

Create a Graph, print it◆ solutions
Implement BFS algorithm◆ solutions
Implement DFS Algo◆ solutions
Detect Cycle in Directed Graph using BFS/DFS Algo◆ solutions
Detect Cycle in UnDirected Graph using BFS/DFS Algo◆ solutions
Search in a Maze◆ solutions
Minimum Step by Knight◆ solutions
flood fill algo◆ solutions
Clone a graph◆ solutions
Making wired Connections◆ solutions
word Ladder◆ solutions
Dijkstra algo◆ solutions
Implement Topological Sort◆ solutions
Minimum time taken by each job to be completed given by a Directed Acyclic Graph◆ solutions
Find whether it is possible to finish all tasks or not from given dependencies◆ solutions
Find the no. of Isalnds◆ solutions
Given a sorted Dictionary of an Alien Language, find order of characters◆ solutions
Implement Kruksal’sAlgorithm◆ solutions
Implement Prim’s Algorithm◆ solutions
Total no. of Spanning tree in a graph◆ solutions
Implement Bellman Ford Algorithm◆ solutions
Implement Floyd warshallAlgorithm◆ solutions
Travelling Salesman Problem◆ solutions
Graph ColouringProblem◆ solutions
Snake and Ladders Problem◆ solutions
Find bridge in a graph◆ solutions
Count Strongly connected Components(Kosaraju Algo)◆ solutions
Check whether a graph is Bipartite or Not◆ solutions
Detect Negative cycle in a graph◆ solutions
Longest path in a Directed Acyclic Graph◆ solutions
Journey to the Moon◆ solutions
Cheapest Flights Within K Stops◆ solutions
Oliver and the Game◆ solutions
Water Jug problem using BFS◆ solutions
Water Jug problem using BFS◆ solutions
Find if there is a path of more thank length from a source◆ solutions
M-ColouringProblem◆ solutions
Minimum edges to reverse o make path from source to destination◆ solutions
Paths to travel each nodes using each edge(Seven Bridges)◆ solutions
Vertex Cover Problem◆ solutions
Chinese Postman or Route Inspection◆ solutions
Number of Triangles in a Directed and Undirected Graph◆ solutions
Minimise the cashflow among a given set of friends who have borrowed money from each other◆ solutions
Two Clique Problem◆ solutions

Trie 0/6

Construct a trie from scratch◆ solutions
Find shortest unique prefix for every word in a given list◆ solutions
Word Break Problem | (Trie solution)◆ solutions
Given a sequence of words, print all anagrams together◆ solutions
Implement a Phone Directory◆ solutions
Print unique rows in a given boolean matrix◆ solutions

Dynamic Programming 0/60

Coin ChangeProblem◆ solutions
Knapsack Problem◆ solutions
Binomial CoefficientProblem◆ solutions
Permutation CoefficientProblem◆ solutions
Program for nth Catalan Number◆ solutions
Matrix Chain Multiplication◆ solutions
Edit Distance◆ solutions
Subset Sum Problem◆ solutions
Friends Pairing Problem◆ solutions
Gold Mine Problem◆ solutions
Assembly Line SchedulingProblem◆ solutions
Painting the Fenceproblem◆ solutions
Maximize The Cut Segments◆ solutions
Longest Common Subsequence◆ solutions
Longest Repeated Subsequence◆ solutions
Longest Increasing Subsequence◆ solutions
Space Optimized Solution of LCS◆ solutions
LCS (Longest Common Subsequence) of three strings◆ solutions
Maximum Sum Increasing Subsequence◆ solutions
Count all subsequences having product less than K◆ solutions
Longest subsequence such that difference between adjacent is one◆ solutions
Maximum subsequence sum such that no three are consecutive◆ solutions
Egg Dropping Problem◆ solutions
Maximum Length Chain of Pairs◆ solutions
Maximum size square sub-matrix with all 1s◆ solutions
Maximum sum of pairs with specific difference◆ solutions
Min Cost PathProblem◆ solutions
Maximum difference of zeros and ones in binary string◆ solutions
Minimum number of jumps to reach end◆ solutions
Minimum cost to fill given weight in a bag◆ solutions
Minimum removals from array to make max –min <= K◆ solutions
Longest Common Substring◆ solutions
Count number of ways to reacha given score in a game◆ solutions
Count Balanced Binary Trees of Height h◆ solutions
LargestSum Contiguous Subarray ★◆ solutions
Smallest sum contiguous subarray◆ solutions
Unbounded Knapsack (Repetition of items allowed)◆ solutions
Word Break Problem◆ solutions
Largest Independent Set Problem◆ solutions
Partition problem◆ solutions
Longest Palindromic Subsequence◆ solutions
Count All Palindromic Subsequence in a given String◆ solutions
Longest Palindromic Substring◆ solutions
Longest alternating subsequence◆ solutions
Weighted Job Scheduling◆ solutions
Coin game winner where every player has three choices◆ solutions
Count Derangements (Permutation such that no element appears in its original position) ★◆ solutions
Maximum profit by buying and selling a share at most twice ★◆ solutions
Optimal Strategy for a Game◆ solutions
Optimal Binary Search Tree◆ solutions
Palindrome PartitioningProblem◆ solutions
Word Wrap Problem◆ solutions
Mobile Numeric Keypad Problem ★◆ solutions
Boolean Parenthesization Problem◆ solutions
Largest rectangular sub-matrix whose sum is 0◆ solutions
Largest area rectangular sub-matrix with equal number of 1’s and 0’s ★◆ solutions
Maximum sum rectangle in a 2D matrix◆ solutions
Maximum profit by buying and selling a share at most k times◆ solutions
Find if a string is interleaved of two other strings◆ solutions
Maximum Length of Pair Chain◆ solutions

Bit Manipulation 0/10

Count set bits in an integer◆ solutions
Find the two non-repeating elements in an array of repeating elements◆ solutions
Count number of bits to be flipped to convert A to B◆ solutions
Count total set bits in all numbers from 1 to n◆ solutions
Program to find whether a no is power of two◆ solutions
Find position of the only set bit◆ solutions
Copy set bits in a range◆ solutions
Divide two integers without using multiplication, division and mod operator◆ solutions
Calculate square of a number without using *, / and pow()◆ solutions
Power Set◆ solutions