Question 1: Arrays: Find numbers with even number of digits
Question 2: Arrays: Find unique numbers that sum upto zero
Question 3: Arrays: Find the k’th smallest/largest element in an array
Question 4: Arrays: Check If N and Its Double Exist
Question 5: Arrays: Move all the negative number in beginning
Question 6: Arrays: Find the union and intersection of two sorted arrays
Question 7: Arrays: Given an array, rotate it one time
Question 8: Arrays: Given an array, find the continuous sub array that has the largest sum, return the sum. 2 solutions in C++
Question 9: Arrays: Minimize the maximum difference between the heights
Question 10: Arrays: Reach the end of the array with minimum jumps. Solution in C++
Question 11: Arrays: Given an array find the duplicate number
Question 12: Arrays: Merge Two Sorted arrays without using extra space
Question 13: Arrays: Kadane Algorithm
Question 14: Arrays: Merge overlapping Intervals solution in C++
Question 15: Arrays: Implement next permutation, which rearranges numbers into the next greater permutation of numbers.
Question 16: Arrays: Inversion Count in an Array
Question 17: Arrays: Optimum Time to Buy and Sell Stock
Question 18: Arrays: Given an unsorted array, and a key. Find 2 elements such that the difference between the elements is equal to the key.
Question 19: Arrays: Find common element in 3 sorted arrays.
Question 20: Arrays: Rearrange the array with one positive and one negative number.
Question 21: Arrays: Given an array, find 3 elements such that [a + b + c] = 0. Find all the 3 unique elements.
Question 22: Arrays: Check if 3 consecutive odds exist
Question 23: Arrays: Given an integer array, find the maximum product made from continuous elements in that array.
Question 24: Arrays: Longest Increasing Subsequence
Question 25: Arrays: Given an array, find the majority element
Question 26: Arrays: Merge sorted array inplace
Question 27: Arrays: Find whether an array is subset of another array
Question 28: Arrays: Find a triplet that sum to a given value
Question 29: Arrays: Rain water trapping
Question 30: Arrays: Find triplet with minimum sum
Question 31: Arrays: Given an array of non repeating numbers and a key, find all the unique combinations in that array
Question 32: Arrays: Three way partitioning of an array around a given range
Question 33: Arrays: Minimum swaps required to bring all elements less than or equal to k together
Question 34: Arrays: Get minimum number of merge operations to make an array palindrome
Question 35: Arrays: Find the median of 2 sorted arrays of same size
Question 36: Arrays: Program to check if an Array is Palindrome or not
Question 37: Sort an array of 0s, 1s and 2s in C
Question 38: Given an array, the difference between the elements is one, find if the “key” element is present or not.
Question 1: Matrix: Given a matrix of m x n elements , print all elements of the matrix in spiral order
Question 2: Matrix: Given a 2D Matrix and a key element, search and return if element is present or not
Question 3: Matrix: Find median in a row wise sorted matrix
Question 4: Matrix: Find a row with maximum number of 1’s in a binary matrix
Question 5: Matrix: Given a m x n matrix, if an element is 0, set its entire row and column to 0
Question 6: Matrix: Given a positive integer n, generate a square matrix filled with elements from 1 to n^2 in spiral order
Question 7: Matrix: Find pair with maximum sum in the matrix.
Question 8: Matrix: Given an n x n 2D matrix rotate it by 90 degrees
Question 9: Matrix: Kth smallest element in a sorted matrix
Question 1o: Matrix: Get the common elements in all row of a matrix.
Question 1: Strings: Reverse a string
Question 2: Strings: Remove all consecutive duplicates from the string
Question 3: Strings: Print all the duplicates in a string
Question 4: Strings: Given a string convert into its equivalent ASCII form
Question 5: Strings: Program to check if strings are rotations of each other or not
Question 6: Strings: Second most repeated word in a sequence
Question 7: Strings: Minimum Number of Swaps to Make the Binary String Alternating
Question 8: Strings: Given a string find the longest Palindromic Substring
Question 9: Strings: Longer Contiguous Segments of Ones than Zeros
Question 1o: Strings: Given a string, print all the subsequence
Question 11: Strings: Permutations of a given string
Question 12: Strings: Divide binary string into sub strings with equal number of 0s and 1s.
Question 13: Strings: Given a sentence and maxWidth. Arrange the text in such a way that each line has exactly maxWidth characters
Question 14: Strings: Min Edit Distance
Question 15: Strings: Longest Substring Of All Vowels in Order
Question 16: Strings: Check balanced parenthesis
Question 17: Strings: Check if it is possible to re-arrange characters in a string, such a way that no two adjacent are same
Question 18: Strings: Rabin Karp algorithm
Question 19: Strings: Knuth Morris Pratt String matching algorithm
Question 2o: Strings: Convert a string into its mobile numeric keypad
Question 21: Strings: Get the minimum number of inversions needed to make an expression balanced
Question 22: Strings: Given a string return all the substring that is a palindrome
Question 23: Strings: Count the number of string in 2D character array
Question 24: Strings: Given 2D matrix and a word, find if the word exists in the grid
Question 25: Strings: Boyer Moore algorithm
Question 26: Strings: Convert Roman Numerals to Decimal
Question 27: Strings: Longest Common Prefix
Question 28: Strings: Minimum number of flips to make binary string alternate
Question 29: Strings: Minimum swaps required for bracket balancing
Question 3o: Strings: Find the first repeated word in a string
Question 31: Strings: Find the longest common subsequence between two strings.
Question 32: Strings: Given a string of integers, restore all valid IP addresses
Question 33: Strings: Smallest distinct window
Question 34: Strings: Check if it is possible to re-arrange characters in a string, such a way that no two adjacent are same
Question 35: Strings: Check if Word Equals Summation of Two Words
Question 36: Strings: Group Anagrams
Question 37: Strings: Minimum Window Substring
Question 38: Strings: Remove all consecutive duplicates from the string
Question 39: Strings: Wildcard Matching
Question 4o: Strings: Longest Prefix Suffix
Question 41: Strings: Find minimum operations required to transform a string into another string
Question 42: Strings: Given 2 strings, check if they are isomorphic strings
Question 43: Strings: Recursively print all sentences that can be formed from list of word lists
Question 44: Strings: Number of Different Integers in a String
Searching & Sorting
Question 1: Searching & Sorting: Find the first and last occurrence of an element
Question 2: Searching and Sorting: Get the fixed point in an array
Question 3: Searching & Sorting: Given an array sorted in ascending order and is rotated at some pivot, given a target value to search, if found in the array return its index
Question 4: Searching & Sorting: Calculate the square of a number and also check if that number is even or odd using bitwise operator.
Question 5: Searching and Sorting: Maximum and minimum of an array using minimum number of comparisons
Question 6: Searching and Sorting: Binary search on an array that is in descending order
Question 7: Searching and Sorting: Order-Agnostic Binary Search
Question 8: Searching and Sorting: Find the majority element in the array
Question 9: Searching and Sorting: Search an array where adjacent differ by at most k
Question 1o: Searching and Sorting: Count all distinct pairs with difference equal to k
Question 11: Searching and Sorting: Given an array n integers and an integer key, are there four elements a, b, c, and d in the array such that a + b + c + d = key? Find all unique quadruplets in the array which gives the sum of key.
Question 12: Searching and Sorting: Maximum sum such that no two elements are adjacent
Question 13: Searching and Sorting: Given an array of n integers and an integer “key”, find three integers in the array such that the sum is closest to key.
Question 14: Searching and Sorting: Merge 2 sorted arrays
Question 15: Searching and Sorting: print all subarrays with 0 sum
Question 16: Searching and Sorting: Product of array except itself
Question 17: Searching and Sorting: Sort Integers by The Number of 1 Bits
Question 18: Searching and Sorting: Minimum number of swaps required to sort an array
Question 19: Searching and Sorting: Find the smallest and second smallest elements in an array
Question 2o: Searching and Sorting: Find the number of times a Sorted array is Rotated
Question 21: Searching and Sorting: Searching in a Nearly Sorted Array
Question 22: Searching and Sorting: Find the minimum element from an array that is sorted and is rotated
Question 23: Searching and Sorting: K-th Element of Two Sorted Arrays
Question 24: Searching and Sorting: Find Floor of an element in a Sorted Array
Question 25: Searching and Sorting: Find Ceil of an element in a Sorted Array
Question 26: Searching and Sorting: Find position of an element in an Infinite Sorted Array
Question 27: Searching and Sorting: Job Sequencing with deadline Problem
Question 28: Searching and Sorting: Find the missing number in Arithmetic Progression
Question 29: Searching and Sorting: Factorial Trailing Zeroes
Question 3o: Searching and Sorting: Find the index of first 1 in an infinite sorted array of 0s and 1s
Question 31: Searching and Sorting: Peak Element
Question 32: Searching and Sorting: Find maximum element in Bitonic Array
Question 33: Searching and Sorting: Given a set of distinct integers, nums, return all possible subsets in CPP
Question 34: Searching and Sorting: Search An Element in Bitonic Array
Question 35: Searching and Sorting: Get the rotation count in sorted rotated array
Question 36: Searching and Sorting: Count the number of 1’s in an array sorted in decreasing order.
Question 1: Linked List: Reverse Linked List iterative and recursive
Question 2: Linked List: Reverse Linked List in groups
Question 3: Linked List: Given a linked list, check if it has a cycle in it, solution in C++
Question 4: Linked List: Rotate linked list by k nodes
Question 5: Linked List: Given a linked list, if it has a cycle, get the node where the cycle begins else return NULL.
Question 6: Linked List: Given a linked list with duplicates, remove the nodes with duplicates and keep only distinct numbers
Question 7: Linked List: Remove duplicates from an unsorted linked list
Question 8: Linked List: Move last element to front of a given Linked List
Question 9: Linked List: Add 1 to the linked list
Question 1o: Linked List: Given two non empty Linked List with non negative numbers, and numbers are stored in reverse order having single digit.
Question 11: Linked List: Find Intersection of Two Linked Lists
Question 12: Linked List: You are given a linked list and a key “x”, partition the list in such a way that, all the nodes less than “x” comes before the nodes greater than or equal to “x”
Question 13: Linked List: Given an unsorted linked list, sort the list using merge sort
Question 14: Linked List: Reverse Linked List given 2 points m and n
Question 15: Linked List: Find middle element in Linked List
Question 16: Linked List: Perform below operations on Circular Singly Linked List
Question 17: Linked List: Split circular Linked List into two halves
Question 18: Linked List: Program to Check if a Singly Linked List is Palindrome
Question 19: Linked List: Deletion from a Circular Linked List
Question 2o: Linked List: Reverse a Doubly Linked List
Question 21: Linked List: Find pairs with a given sum in a DLL.
Question 22: Linked List: Count triplets in a sorted DLL whose sum is equal to given value “k”.
Question 23: Linked List: Sort a “k”sorted Doubly Linked list
Question 24: Linked List: Rotate Doubly linked list by N nodes
Question 25: Linked List: Rotate a Doubly Linked list in group of Given Size
Question 26: Linked List: Merge two sorted linked lists and return it as a new list
Question 27: Linked List: Given linked list swap Nodes in Pairs
Question 28: Linked List: Flatten a Linked List
Question 29: Linked List: Given a linked list such that each node contains an additional random pointer which could point to any node in the list or null. Return the deep copy of the list
Question 3o: Linked List: Merge k sorted linked lists and return it as one sorted list in C++
Question 31: Linked List: Multiply two numbers represented by Linked Lists
Question 32: Linked List: Delete nodes which have a greater value on right side using recursion
Question 33: Linked List: Segregate even and odd nodes in a Linked List
Question 34: Linked List: Given a linked list Remove Nth Node From End of List
Question 35: Linked List: Odd Even Linked List
Question 1: Binary Trees: Level Order Traversal
Question 2: Binary Trees: Display Reverse Level Order Traversal by using queue
Question 3: Binary Trees: Height or Max depth of a BTree
Question 4: Binary Trees: Diameter of a Binary Tree
Question 5: Binary Trees: Convert a binary tree to its Mirror Tree
Question 6: Binary Trees: Perform InOrder traversal on a Binary Tree by without Recursion
Question 7: Binary Trees: Perform PreOrder traversal on a Binary Tree by without Recursion
Question 8: Binary Trees: Perform PostOrder traversal on a Binary Tree by without Recursion
Question 9: Binary Trees: Left view and right view of a Binary Tree
Question 1o: Binary Trees: Check if Binary Tree is Foldable Tree
Question 11: Binary Trees: Top view of a binary tree
Question 12: Binary Trees: Bottom view of binary Tree
Question 13: Binary Trees: Spiral order or Zigzag traversal of a Binary Tree
Question 14: Binary Trees: Check if binary tree is a height balanced tree?
Question 15: Binary Trees: Diagonal Traversal of a Binary tree
Question 16: Binary Trees: Boundary Traversal of Binary Tree
Question 17: Binary Trees: Get Maximum width of Binary Tree
Question 18: Binary Trees: Convert Binary Tree to DLL
Question 19: Binary Trees: Convert Binary tree into Sum tree
Question 2o: Binary Trees: Construct Binary Tree from preorder and inorder traversal
Question 21: Binary Trees: Minimum swap required to convert binary tree to binary search tree
Question 22: Binary Trees: Check if binary tree is a sum tree
Question 23: Binary Trees: Check if all Leaf Nodes are at same level in Binary tree
Question 24: Binary Trees: Find Duplicate Subtrees
Question 25: Binary Trees: Check if Two Trees are Mirror Structure to each other
Question 26: Binary Trees: Get Sum of all nodes formed from Root to Leaf Path
Question 27: Binary Trees: Check if a given graph is tree or not
Question 28: Binary Trees: Find largest subtree sum in a tree
Question 29: Binary Trees: Maximum Sum of nodes in Binary tree such that no two are adjacent
Question 3o: Binary Trees: Print all the paths from root node to leaf node
Question 31: Binary Trees: Lowest Common ancestor of a Binary Tree.
Question 32: Binary Trees: Print the nodes at k distance from the root of a binary tree
Question 33: Binary Trees: Kth Ancestor of a Tree Node
Question 34: Binary Trees: Find Duplicate Subtrees
Question 35: Binary Trees: Check if two Binary Trees are Isomorphic
Binary Search Trees
Question 1: Binary Search Trees: Find a value in a BST
Question 2: Binary Search Trees: Deletion of a node in a BST
Question 3: Binary Search Trees: Find min and max value in a BST
Question 4: Binary Search Trees: Find the Inorder predecessor and successor for a given key in BST
Question 5: Binary Search Trees: A program to check if a binary tree is BST or not
Question 6: Binary Search Trees: Convert a BST into greater sum tree
Question 7: Binary Search Trees: LCA in a BST
Question 8: Binary Search Trees: Construct BST from preorder traversal
Question 9: Binary Search Trees: Convert Binary Tree into Binary Search Tree.
Question 1o: Binary Search Trees: Convert a normal BST into a Balanced BST
Question 11: Binary Search Trees: Merge Two balanced BST
Question 12: Binary Search Trees: Kth Largest Element in a BST
Question 13: Binary Search Trees: Kth smallest Element in a BST
Question 14: Binary Search Trees: Return the sum of given range in BST.
Question 15: Binary Search Trees: Get the Shortest distance between two nodes in BST
Question 16: Binary Search Trees: Count the number of BST nodes that lie in a given range.
Question 17: Binary Search Trees: Convert sorted DLL to Balanced BST
Question 18: Binary Search Trees: Find triplet sum in BST
Question 19: Binary Search Trees: Check if the pre-order is a valid BST
Question 2o: Binary Search Trees: Check if the BST has a dead end
Question 21: Binary Search Trees: Correct a BST where 2 nodes are swapped
Question 22: Binary Search Trees: Flatten BST to sorted list
Question 1: Greedy: Activity Selection Problem
Question 2: Greedy: Job Sequencing with deadline Problem
Question 3: Greedy: Remove duplicates from a string
Question 4: Greedy: Add elements in an array so the sum is equal to the given range
Question 5: Greedy: Fractional knapsack tutorial with implementation
Question 7: Greedy: Remove k digits from an number to make it a smallest integer.
Question 8: Greedy: Get the minimum platforms needed to avoid delay in the train arrival.
Question 9: Greedy: Check if the string is a substring of another string
Question 1o: Greedy: Remove overlapping intervals.
Question 11: Greedy: Plant n flowers in flower bed
Question 12: Greedy: Maximum meetings in one room
Question 13: Greedy: Distribute Candy
Question 14: Greedy: Shuffle array so that one array element is greater than other array element
Question 15: Greedy: Schedule task efficiently
Question 16: Greedy: Partition characters
Question 17: Greedy: Maximum sum of absolute difference of an array
Question 18: Greedy: Juice change
Question 19: Greedy: Given a string, split into balanced strings.
Question 2o: Greedy: Perform operations on a broker calculator
Question 21: Greedy: Add minimum to make parentheses valid.
Question 22: Greedy: Remove covered intervals.
Question 24: Greedy: Reduce the array size to the half
Question 25: Greedy: Connect ropes with minimum cost.
Question 26: Dijkstra’s Algorithm
Question 28: Kruskal’s algorithm
Question 29: Greedy: Connect ropes with minimum cost.
Question 32: Greedy: Find maximum sum possible equal sum of three stacks
Question 1: Backtracking: Partition string into its palindrome
Question 2: Backtracking: Letter Combinations of a Phone Number
Question 3: Backtracking: Solve Sudoku
Question 4: Backtracking: Check if the given board is valid Sudoku or not
Question 5: Backtracking: N-Queens
Question 6: Backtracking: Given an input string (s) and a pattern (p), implement regular expression matching with support for ‘.’ and ‘*’
Question 7: BackTracking: Given a collection of numbers that might contain duplicates, return all possible unique permutations
Question 8: Backtracking: You are given an array with repeated elements and a key element, find all unique combination to the key
Question 9: Backtracking: Get the k combination from an array of 1 to n
Question 1o: Backtracking: Given array of integers that might contain duplicates, return all the subsets
Question 11: Backtracking: Find combination sum of k numbers that sum up to n
Question 12: Backtracking: Given a collection of candidate numbers and a key, find all unique combinations in candidates where the candidate numbers sums to target
Question 13: Backtracking: Letter case permutation
Question 14: Backtracking: Return the number of queens possible in a chessboard
Question 15: Backtracking: Get the sequential digits from the given range
Question 16: Backtracking: Partition to K Equal Sum Subsets
Question 17: Backtracking: Get maximum sum in a matrix
Question 1: Given an array of integers in ascending order, return index of the two numbers such that they add up to a specific key provided.
Question 1: Given an array of integers in ascending order, return index of the two numbers such that they add up to a specific key provided.
Top-Down and/or Bottom Up approach
Question 1: Count the number of ways a baby can reach the nth stair taking 1 or 2 steps at a time in C language.