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Arrays

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

Matrix

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

String

Reverse a String
Check whether a String is Palindrome or not
Find Duplicate characters in a string
Write a Code to check whether one string is a rotation of another
Write a Program to check whether a string is a valid shuffle of two strings or not
Count and Say problem
Write a program to find the longest Palindrome in a string.[ Longest palindromic Substring]
Find Longest Recurring Subsequence in String
Print all Subsequences of a string.
Print all the permutations of the given string
Split the Binary string into two substring with equal 0’s and 1’s
Word Wrap Problem [VERY IMP].
EDIT Distance [Very Imp]
Find next greater number with same set of digits. [Very Very IMP]
Balanced Parenthesis problem.[Imp]
Word break Problem[ Very Imp]
Rabin Karp Algo
KMP Algo
Convert a Sentence into its equivalent mobile numeric keypad sequence.
Minimum number of bracket reversals needed to make an expression balanced.
Count All Palindromic Subsequence in a given String.
Count of number of given string in 2D character array
Search a Word in a 2D Grid of characters.
Boyer Moore Algorithm for Pattern Searching.
Converting Roman Numerals to Decimal
Longest Common Prefix

Searching & Sorting

Find first and last positions of an element in a sorted array
Find a Fixed Point (Value equal to index) in a given array
Search in a rotated sorted array
square root of an integer
Maximum and minimum of an array using minimum number of comparisons
Optimum location of point to minimize total distance
Find the repeating and the missing
find majority element
Searching in an array where adjacent differ by at most k
find a pair with a given difference
find four elements that sum to a given value
maximum sum such that no 2 elements are adjacent
Count triplet with sum smaller than a given value
merge 2 sorted arrays
print all subarrays with 0 sum
Product array Puzzle
Sort array according to count of set bits
minimum no. of swaps required to sort the array
Bishu and Soldiers
Rasta and Kheshtak
Kth smallest number again
Find pivot element in a sorted array
K-th Element of Two Sorted Arrays

Binary Tress

level order traversal
Reverse Level Order traversal
Height of a tree
Diameter of a tree
Mirror of a tree
Inorder Traversal of a tree both using recursion and Iteration
Preorder Traversal of a tree both using recursion and Iteration
Postorder Traversal of a tree both using recursion and Iteration
Left View of a tree
Right View of Tree
Top View of a tree
Bottom View of a tree
Zig-Zag traversal of a binary tree
Check if a tree is balanced or not
Diagnol Traversal of a Binary tree
Boundary traversal of a Binary tree
Construct Binary Tree from String with Bracket Representation
Convert Binary tree into Doubly Linked List
Convert Binary tree into Sum tree
Construct Binary tree from Inorder and preorder traversal
Find minimum swaps required to convert a Binary tree into BST
Check if Binary tree is Sum tree or not

Binary Search Trees

Fina a value in a BST
Deletion of a node in a BST
Find min and max value in a BST
Find inorder successor and inorder predecessor in a BST
Check if a tree is a BST or not
Populate Inorder successor of all nodes
Find LCA of 2 nodes in a BST
Construct BST from preorder traversal
Convert Binary tree into BST
Convert a normal BST into a Balanced BST
Merge two BST [ V.V.V>IMP ]
Find Kth largest element in a BST
Find Kth smallest element in a BST
Count pairs from 2 BST whose sum is equal to given value "X"

Greedy

Activity Selection Problem
Job SequencingProblem
Huffman Coding
Water Connection Problem
Fractional Knapsack Problem
Greedy Algorithm to find Minimum number of Coins
Maximum trains for which stoppage can be provided
Minimum Platforms Problem
Buy Maximum Stocks if i stocks can be bought on i-th day
Find the minimum and maximum amount to buy all N candies
Minimize Cash Flow among a given set of friends who have borrowed money from each other
Minimum Cost to cut a board into squares
Check if it is possible to survive on Island
Find maximum meetings in one room

Backtracking

Rat in a maze Problem
Printing all solutions in N-Queen Problem
Word Break Problem using Backtracking
Remove Invalid Parentheses
Sudoku Solver
m Coloring Problem
Print all palindromic partitions of a string
Subset Sum Problem
The Knight’s tour problem
Tug of War
Find shortest safe route in a path with landmines
Combinational Sum
Find Maximum number possible by doing at-most K swaps
Print all permutations of a string
Find if there is a path of more than k length from a source

Stacks & Queues

Implement Stack from Scratch
Implement Queue from Scratch
Implement 2 stack in an array
find the middle element of a stack
Implement "N" stacks in an Array
Check the expression has valid or Balanced parenthesis or not.
Reverse a String using Stack
Design a Stack that supports getMin() in O(1) time and O(1) extra space.
Find the next Greater element
The celebrity Problem
Arithmetic Expression evaluation
Evaluation of Postfix expression
Implement a method to insert an element at its bottom without using any other data structure.
Reverse a stack using recursion
Sort a Stack using recursion
Merge Overlapping Intervals
Largest rectangular Area in Histogram
Length of the Longest Valid Substring
Expression contains redundant bracket or not
Implement Stack using Queue

Heap

Implement a Maxheap/MinHeap using arrays and recursion.
Sort an Array using heap. (HeapSort)
Maximum of all subarrays of size k.
“k” largest element in an array
Kth smallest and largest element in an unsorted array
Merge “K” sorted arrays. [ IMP ]
Merge 2 Binary Max Heaps
Kth largest sum continuous subarrays
Leetcode- reorganize strings
Merge “K” Sorted Linked Lists [V.IMP]

Graphs

Create a Graph, print it
Implement BFS algorithm
Implement DFS Algo
Detect Cycle in Directed Graph using BFS/DFS Algo
Detect Cycle in UnDirected Graph using BFS/DFS Algo
Search in a Maze
Minimum Step by Knight
flood fill algo
Clone a graph
Making wired Connections
word Ladder
Dijkstra algo
Implement Topological Sort
Minimum time taken by each job to be completed given by a Directed Acyclic Graph
Find whether it is possible to finish all tasks or not from given dependencies
Find the no. of Isalnds
Given a sorted Dictionary of an Alien Language, find order of characters
Implement Kruksal’sAlgorithm
Implement Prim’s Algorithm
Total no. of Spanning tree in a graph
Implement Bellman Ford Algorithm
Implement Floyd warshallAlgorithm
Travelling Salesman Problem
Graph ColouringProblem
Snake and Ladders Problem
Find bridge in a graph
Count Strongly connected Components(Kosaraju Algo)
Check whether a graph is Bipartite or Not
Detect Negative cycle in a graph
Longest path in a Directed Acyclic Graph

Trie

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

Dynamic Programming

Coin ChangeProblem
Knapsack Problem
Binomial CoefficientProblem
Permutation CoefficientProblem
Program for nth Catalan Number
Matrix Chain Multiplication
Edit Distance
Subset Sum Problem
Friends Pairing Problem
Gold Mine Problem
Assembly Line SchedulingProblem
Painting the Fenceproblem
Maximize The Cut Segments
Longest Common Subsequence
Longest Repeated Subsequence
Longest Increasing Subsequence
Space Optimized Solution of LCS
LCS (Longest Common Subsequence) of three strings
Maximum Sum Increasing Subsequence
Count all subsequences having product less than K
Longest subsequence such that difference between adjacent is one
Maximum subsequence sum such that no three are consecutive
Egg Dropping Problem
Maximum Length Chain of Pairs
Maximum size square sub-matrix with all 1s
Maximum sum of pairs with specific difference
Min Cost PathProblem
Maximum difference of zeros and ones in binary string
Minimum number of jumps to reach end
Minimum cost to fill given weight in a bag

Bit Manipulation

Count set bits in an integer
Find the two non-repeating elements in an array of repeating elements
Count number of bits to be flipped to convert A to B
Given a sequence of words, print all anagrams together
Divide two integers without using multiplication, division and mod operator
Power Set

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