Must Do Coding Questions Company-wise

Topic :

Google :



  1. Subarray with given sum
  2. Maximum Index
  3. Finding the numbers
  4. Longest valid Parentheses
  5. Jumping Numbers
  6. Connect Nodes at Same Level
  7. Count BST nodes that lie in a given range
  8. Implement LRU Cache
  9. Interleaved Strings
  10. Find triplets with zero sum
  11. Egg Dropping Puzzle
  12. Word Break Problem
  13. Check if a Binary Tree contains duplicate subtrees of size 2 or more
  14. Find largest word in dictionary by deleting some characters of given string
  15. Modular Exponentiation (Power in Modular Arithmetic)

Facebook :

  1. Subarray with given sum
  2. Find all pairs with a given sum
  3. Total Decoding Messages
  4. Word Boggle
  5. Activity Selection
  6. Minimum Depth of a Binary Tree
  7. Implement strstr
  8. Multiply two strings
  9. K-Palindrome
  10. Find triplets with zero sum
  11. Largest subset whose all elements are Fibonacci numbers
  12. Look-and-Say Sequence
  13. Converting Decimal Number lying between 1 to 3999 to Roman Numerals
  14. Convert Ternary Expression to Binary Tree
  15. Maximum Rectangular Area in a Histogram

Amazon :

  1. K largest elements from a big file or array
  2. Reverse a Linked List in groups of given size
  3. Implement a stack with push(), pop() and min() in O(1) time
  4. Add two numbers represented by linked lists
  5. Convert a Binary tree to DLL
  6. Stock span problem
  7. Next larger element
  8. Edit distance
  9. Maximum of all subarrays of size k
  10. Pythagorean Triplet
  11. Print a Binary Tree in Vertical Order
  12. Level order traversal
  13. Smallest window in a string containing all the characters of another string
  14. Find the number of islands
  15. Detect and Remove Loop in a Linked List
  16. Check if a binary tree is BST or not
  17. Boolean Parenthesization
  18. Arrange given numbers to form the biggest number
  19. Implement LRU Cache
  20. Maximum difference between node and its ancestor in Binary Tree

Microsoft :

  1. Key Pair
  2. Is Binary Number Multiple of 3
  3. Kadane’s Algorithm
  4. Missing number in array
  5. Majority Element
  6. Search in a Rotated Array
  7. Check for BST
  8. Finding middle element in a linked list
  9. Root to leaf path sum
  10. Reverse a linked list
  11. Remove every k’th node
  12. Merge 2 sorted linked list in reverse order
  13. Longest Even Length Substring such that Sum of First and Second Half is same
  14. k largest(or smallest) elements in an array | added Min Heap method
  15. Write an Efficient Function to Convert a Binary Tree into its Mirror Tree
  16. Determine if Two Trees are Identical

Adobe :

  1. Search in a Rotated Array
  2. Subset Sum Problem
  3. Reverse words in a given string
  4. Sort an array of 0s, 1s and 2s
  5. Minimum number of jumps
  6. Check for BST
  7. Root to leaf path sum
  8. Sum Tree
  9. Finding middle element in a linked list
  10. Reverse a linked list
  11. Level order traversal in spiral form
  12. Right View of Binary Tree
  13. Remove duplicate element from sorted Linked List
  14. Merge Sort for Linked List
  15. Count set bits in an integer

Oracle :

  1. 0 – 1 Knapsack Problem
  2. Search in a matrix
  3. Power of 2
  4. Palindrome
  5. Root to leaf path sum
  6. Kadane’s Algorithm
  7. Binary Search
  8. Implement Queue using Linked List
  9. Connect Nodes at Same Level
  10. Remove loop in Linked List
  11. Implement Stack using Queues
  12. Implement Queue using Stacks
  13. Remove duplicate element from sorted Linked List
  14. Search in a row wise and column wise sorted matrix
  15. Find the first repeating element in an array of integers

D E Shaw :

  1. Majority Element
  2. Search in a Rotated Array
  3. Sum of Middle Elements of two sorted arrays
  4. Non Repeating Character
  5. Kadane’s Algorithm
  6. Intersection of two sorted Linked lists
  7. Detect Loop in linked list
  8. Print all nodes that don’t have sibling
  9. Two Mirror Trees
  10. Intersection Point in Y Shapped Linked Lists
  11. Trie | (Insert and Search)
  12. Implement Queue using Stacks
  13. Implement Stack using Queues
  14. Find the number of islands
  15. Copy Set Bits in Range

Directi :

  1. Maximum of all subarrays of size k
  2. Search in a matrix
  3. Word Boggle
  4. Jumping Numbers
  5. Transform String
  6. Solve the Sudoku
  7. Find Nth root of M
  8. Array Pair Sum Divisibility Problem
  9. Largest zigzag sequence
  10. Maximum Intervals Overlap
  11. Max rectangle
  12. Maximum path sum
  13. Maximize Dot Product
  14. Excel Sheet | Part – 1
  15. Probability of Knight

MAQ Software :



  1. Sort an array of 0s, 1s and 2s
  2. Permutations of a given string
  3. Rotate Array by n elements
  4. Non Repeating Character
  5. Nth Fibonacci Number
  6. Finding middle element in a linked list
  7. n’th node from end of linked list
  8. Detect Loop in linked list
  9. Implement Queue using Stacks
  10. Find Missing And Repeating
  11. Find the Closest Element in BST
  12. Check if a linked list is Circular Linked List
  13. Reverse a String
  14. Reverse words in a given string
  15. Egg Dropping Puzzle

Yahoo :

  1. First non-repeating character in a stream
  2. Find median in a stream
  3. Largest prime factor
  4. Form coils in a matrix
  5. Word Boggle
  6. Largest Product Palindrome
  7. Surpasser Count
  8. Return two prime numbers
  9. Sort a stack
  10. Three way partitioning
  11. LRU Cache
  12. Serialize and Deserialize a Binary Tree
  13. Split a Circular Linked List into two halves
  14. Interleaved Strings
  15. Max Sum without Adjacents

Accolite :

  1. Count Squares
  2. Longest Prefix Suffix
  3. N-Queen Problem
  4. Coin Change
  5. Permutations of a given string
  6. Stock buy and sell
  7. Longest Palindrome in a String
  8. Sum of two numbers represented as arrays
  9. Max sum submatrix
  10. Maximum sum Rectangle
  11. Root to leaf path sum
  12. Lowest Common Ancestor in a Binary Tree
  13. Level order traversal in spiral form
  14. Implement Stack using Queues
  15. n’th node from end of linked list

Walmart Labs :

  1. Longest consecutive subsequence
  2. Largest number in K swaps
  3. k largest elements
  4. Word Break
  5. Find the highest occurring digit in prime numbers in a range
  6. Count all possible paths from top left to bottom right
  7. Minimum Platforms
  8. Parenthesis Checker
  9. Implement LRU Cache
  10. Josephus Problem
  11. Top View of Binary Tree
  12. Intersection of Two Linked Lists
  13. Alien Dictionary
  14. Remove Loop in Linked List
  15. Wildcard Pattern Matching

Samsung :

  1. Longest Increasing Subsequence
  2. Next larger element
  3. Permutations of a given string
  4. Next greater number set digits
  5. Finding middle element in a linked list
  6. Root to leaf path sum
  7. Detect Loop in linked list
  8. Left View of Binary Tree
  9. Implement Queue using Linked List
  10. Egg Dropping Puzzle
  11. Total number of possible Binary Search Trees with n keys
  12. Count number of bits to be flipped to convert A to B
  13. Implement two stacks in an array
  14. Given only a pointer/reference to a node to be deleted in a singly linked list, how do you delete it?

Paytm :

  1. Sort an array of 0s, 1s and 2s
  2. Reverse words in a given string
  3. Reverse a linked list
  4. Reverse a Linked List in groups of given size
  5. Max Sum without Adjacents
  6. Mirror Tree
  7. Flattening a Linked List
  8. Check for Balanced Tree
  9. Find the number of islands
  10. Coin Change
  11. Count frequencies of all elements in array in O(1) extra space and O(n) time
  12. Convert array into Zig-Zag fashion
  13. Find the row with maximum number of 1s
  14. Maximum Rectangular Area in a Histogram

Ola Cabs :

  1. Kadane’s Algorithm
  2. Missing number in array
  3. Sort an array of 0s, 1s and 2s
  4. Search in a matrix
  5. Left View of Binary Tree
  6. Mirror Tree
  7. Connect Nodes at Same Level
  8. K distance from root
  9. Level order traversal in spiral form
  10. Non Repeating Character
  11. Find the number of islands
  12. Find the character in first string that is present at minimum index in second string
  13. Maximum difference between two elements such that larger element appears after the smaller number
  14. Find the element that appears once in sorted array
  15. Boolean Matrix Problem

Flipkart :

  1. Kadane’s Algorithm
  2. 0 – 1 Knapsack Problem
  3. Inversion of array
  4. Consecutive 1’s not allowed
  5. Finding middle element in a linked list
  6. Get minimum element from stack
  7. Left View of Binary Tree
  8. Add two numbers represented by linked lists
  9. Connect Nodes at Same Level
  10. Sum of dependencies in a graph
  11. Maximum of all subarrays of size k
  12. Possible words from Phone digits
  13. Reverse Level Order Traversal
  14. Implement Queue using Stack
  15. Maximum Width of Tree

SAP Labs :



  1. Sort an array of 0s, 1s and 2s
  2. Check if a number is Bleak
  3. Reverse words in a given string
  4. Remove Spaces from string
  5. Second Largest
  6. Check if a number is power of another number
  7. Reverse a linked list
  8. Get minimum element from stack
  9. BFS traversal of graph
  10. Find median in a stream of integers
  11. Quick Sort
  12. GCD of Array
  13. LCM And GCD
  14. Heap Sort
  15. Bubble Sort

VMware :

  1. Longest Common Subsequence
  2. Maximum Index
  3. Array to BST
  4. Egg Dropping Puzzle
  5. K’th smallest element
  6. Check for BST
  7. Finding middle element in a linked list
  8. Reverse a linked list
  9. Detect Loop in linked list
  10. Run Length Encoding
  11. Height of Binary Tree
  12. Infix to Postfix
  13. Diameter of Binary Tree
  14. Mirror Tree
  15. Boolean Matrix Problem

Cisco :

  1. Missing number in array
  2. Reverse words in a given string
  3. Permutations of a given string
  4. Array to BST
  5. Counbt set bits
  6. Reverse a linked list
  7. Level order traversal
  8. Minimum Spanning Tree
  9. Does array represent Heap
  10. Kth largest element in a stream
  11. Escape the jail
  12. K’th smallest element
  13. Insertion Sort
  14. Bubble Sort

Goldman Sachs :

  1. Reverse words in a given string
  2. Overlapping rectangles
  3. Column name from a given column number
  4. Non Repeating Character
  5. Total Decoding Messages
  6. Sum Tree
  7. Get minimum element from stack
  8. Flattening a Linked List
  9. Sort a stack using Recursion
  10. Intersection Point in Y Shapped Linked Lists
  11. Stock buy and sell
  12. Egg Dropping Puzzle
  13. Check for Balanced Tree
  14. Check if two arrays are equal or not
  15. Implement Queue using Stacks

MakeMyTrip :

  1. Distinct palindromic substrings
  2. Two water Jug problem
  3. Minimum Cost Path
  4. Transpose of Matrix
  5. Smallest window in a string containing all the characters of another string
  6. Check Mirror in N-ary tree
  7. Longest Prefix Suffix
  8. Maximum Difference
  9. Nuts and Bolts Problem
  10. N meetings in one room
  11. String formation from substring
  12. Longest Common Subsequence
  13. Next Permutation
  14. Trailing zeroes in factorial
  15. Egg Dropping Puzzle

Snapdeal :

  1. Fighting the darkness
  2. Money Division
  3. Group Anagrams Together
  4. Pangram Strings
  5. 0 – 1 Knapsack Problem
  6. Longest Arithmetic Progression
  7. Next greater number set digits
  8. Number of Coins
  9. Check If two Line segments Intersect
  10. Two numbers with sum closest to zero
  11. Parenthesis Checker
  12. Maximum Rectangular Area in a Histogram
  13. Smallest Positive missing number
  14. Find the number of islands
  15. Reverse a Linked List in groups of given size

Qualcomm :

  1. Find length of Loop
  2. Implement strstr
  3. Min distance between two given nodes of a Binary Tree
  4. Delete a node from BST
  5. Left View of Binary Tree
  6. Intersection Point in Y Shapped Linked Lists
  7. Check for BST
  8. Reverse a linked list
  9. Detect Loop in linked list
  10. Reverse Bits
  11. Next Permutation
  12. Array Subset of another array
  13. Set Bits
  14. Find Prime numbers in a range
  15. Subsequence matching

Payu :

  1. Reverse each word in a given string
  2. First non-repeating character in a stream
  3. Next larger element
  4. 0 – 1 Knapsack Problem
  5. Leaders in an array
  6. Trapping Rain Water
  7. Pattern Searching
  8. Implement Atoi
  9. Lowest Common Ancestor in a Binary Tree
  10. Level order traversal in spiral form
  11. Flattening a Linked List
  12. Finding middle element in a linked list
  13. Missing number in array
  14. Kadane’s Algorithm
  15. Count possible ways to construct buildings

Intuit :

  1. Element with left side smaller and right side greater
  2. Find median in a stream
  3. Product array puzzle
  4. Count Occurences of Anagrams
  5. Maximum Sub Array
  6. Binary Array Sorting
  7. Sort a Stack
  8. Find the number of islands
  9. Remove duplicates from an unsorted linked list
  10. Implement LRU Cache
  11. Max Rectangle
  12. Reverse a linked list
  13. Pairwise swap elements of a linked list by swapping data
  14. Find the missing no in string
  15. Depth First Traversal for a Graph

Important Links :

  1. Difficulty-wise ordered Coding questions for Interview and Competitive Programming
  2. Aptitude questions asked in round 1 : Placements Course designed for this purpose.
  3. MCQs asked from different computer science subjects : Subject-Wise Quizzes
  4. Interview theory and coding questions of all companies : Company wise all practice questions.
  5. Interview experiences of all companies : Interview corner.

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