As the placement season is back, GeeksforGeeks is here to help you crack the interview. We have selected some most commonly asked and MUST DO practice problems to crack Product-based Company Interviews.

You can also take part in our mock placement contests which will help you learn different topics and practice at the same time, simulating the feeling of a real placement test environment.

If you are looking for Old MUST DO list, please refer MUST DO Coding Problems for Companies like Amazon, Microsoft, Adobe, …

In case you are a new user, we strongly recommend you to go through the below Improved list.

Note: Now you can track your progress of these questions Must Do Interview Preparation Course.

Topic:

 

Math

• Easy
  • Missing Number in Array
  • Trailing Zeros in Factorial
• Medium
  • A Simple Fraction
• Hard
  • Nth Natural Number
  • Smallest Positive Integer that can not be represented as Sum

Arrays

• Easy
  • Rotate Array
  • Majority Element
  • Plus one
  • Array of alternative +ve and -ve no.s
  • Product Array puzzle
  • Frequencies of Limited Range Array Elements
  • Large Factorial
• Medium
  • Jump Game
  • Maximum number of 1’s
  • Stock Buy and Sell
  • Longest Consecutive Subsequence
  • Maximum value of difference of a pair of elements and their Index
  • Maximum index
  • K-th element of two sorted Arrays
  • Trapping Rain Water
  • 3 sum closest
• Hard 
  • Maximum circular Subarray Sum
  • Merge without Extra Space

Searching

• Easy
  • Search insert position of K in a sorted array
  • Collecting Wood
  • Left most and right most index
  • Bitonic Point 
• Medium
  • Search an element in sorted and rotated array
  • Square root of a number
  • Find missing in second array
• Hard
  • Painter’s Partition Problem
  • Median of 2 sorted arrays of Different sizes
  • Allocate minimum number of pages

Sorting

• Easy
  • Wave array
• Medium
  • Count the number of possible triangles
  • Triplets with sum with given range
  • Count Inversions
  • Relative Sorting
  • Minimum Platforms
  • Maximum Index

Matrix

• Easy 
  • Sort  a 2D vector diagonally
• Medium
  • Spiral Matrix
  • Boolean matrix
  • Rotate matrix by 90 degrees
  • Search in a row-column sorted Matrix
  • Row with maximum 1s

String

• Easy 
  • Reverse words in a given string
  • Longest Common Prefix
  • Roman Number to Integer
• Medium
  • Next higher palindrome number using the same set of digits
  • Length of longest prefix suffix
  • Smallest window in string containing all characters
  • Validate an IP address
  • Implement Atoi
  • Look and say Pattern
  • Longest K unique characters substring

Hashing

• Easy 
  • Key Pair
  • Top K Frequent Elements in Array
  • Intersection of two arrays
  • Array Pair Sum Divisibility Problem
• Medium
  • Triplet Sum in Array
  • Length of the longest substring
  • Is Sudoku Valid
  • Print Anagrams Together 
  • Subarrays with sum K
  • Longest subarray with sum divisible by K

Bit Masking

• Easy 
  • Reverse bits
  • Number of set bits
  • Sum of two integers
  • Check whether K-th bit is set or not
  • Longest Consecutive 1’s
• Medium 
  • Find the element that appears once
  • Gray code
  • Maximum AND
• Hard 
  • Maximum subset XOR
  • Bit Difference

Linked List

• Easy
  • Merge Two Sorted Linked Lists
  • Reverse a Linked List
  • Delete a Node without Head Pointer
  • Add two Numbers represented by linked lists
  • Finding middle element in a linked list
  • Check if linked list is palindrome
• Medium
  • Rearrange a linked list
  • Detect and Remove a loop In Linked List
  • Merge Sort for Linked List
  • Intersection of Linked List
  • Rotate Linked List by K places
  • Flattening a Linked List
  • Reverse a linked list in groups of given size
  • Partition a linked list around a given value
• Hard
  • Clone a linked list with next and random pointers

Stack

• Easy
  • Parenthesis Checker
  • Infix to Postfix
  • Restrictive Candy Crush
• Medium
  • Next Larger Element 
  • Stock span problem
  • The Celebrity Problem
  • Maximum Rectangular Area in a Histogram 
• Hard
  • Longest Valid Parentheses
  • Maximum of minimum for every window size
  • Remove K digits
  • 132 Geeky Buildings

Queue

• Medium
  • Maximum of all subarrays of size K
  • Circular tour (Sliding Window)

Heap

• Easy
  • Rearrange Characters
  • Minimum Cost of ropes
• Medium
  • Kth largest element of stream
  • Merge k sorted arrays
• Hard
  • Median of stream

Binary Tree

• Easy
  • Symmetric Tree
  • Zigzag Tree Traversal
  • Checked for Balanced tree
  • Height of Binary Tree
  • Diameter of Binary tree
  • Determine if two trees are identical
  • Minimum depth of binary tree
• Medium
  • Check if subtree
  • Inorder Traversal (iterative)
  • Preorder Traversal (iterative)
  • Postorder Traversal(iterative)
  • Vertical Traversal of a Binary Tree
  • Construct Binary Tree from Preorder and Inorder Traversal
  • Connect nodes at same level
  • Lowest Common Ancestor of a Binary Tree
  • Boundary Traversal
  • Sum tree
• Hard
  • Binary Tree to Doubly Linked List
  • Maximum sum path between two leaf nodes
  • Burning Tree

Binary Search Tree

• Easy
  • Check for BST
  • Array to BST
  • Inorder Successor in BST
  • Kth Largest Element in a BST
• Medium
  • Remove BST keys outside the given range
  • Pair with given target in BST
  • Unique BSTs
  • Preorder Traversal and BST
• Hard
  • Merge two BST’s
  • Fixing two nodes of a BST

Graph

• Medium
  • Number of Islands
  • COVID Spread
  • Prerequisite tasks
  • Strongly Connected Component
  • Minimum swaps to sort
  • Shortest path
  • Circle of Strings
  • Snake and Ladder Problem 
  • Detect cycle in an undirected graph
  • Detect cycle in a directed graph
  • Check for Bipartite graph
  • Unit Area of Largest region of 1s
• Hard
  • Alien Dictionary
  • Word Ladder

Trie

• Medium
  • Minimum XOR value pair
  • Word Boggle – II
  • Most frequent word in an array of strings
  • Minimum XOR value pair

Greedy

• Medium
  • N meetings in one room
  • Coin Piles
  • Maximize Toys
  • Largest number with given sum
  • Minimize the heights
  • Fractional Knapsack
  • Job Sequencing
  • Police and Thieves
  • Water the Plants

  DP

  • Easy 
    • Count ways to reach the n’th stair
    • Get Minimum Squares
    • Nth Fibonacci Number
  • Medium
    • 0 – 1 Knapsack Problem
    • Number of Coins
    • Edit distance
    • Maximize The Cut Segments
    • Box Stacking
    • Longest Increasing Subsequence
    • Longest Palindromic Substring
    • Longest Common Substring
    • Longest Common Subsequence
    • Wildcard Pattern Matching
    • Total Decoding Messages
    • Max length chain
    • Maximum sum increasing subsequence
    • Minimum number of jumps
    • Subset Sum Problem
    • Maximum path sum in matrix
    • Player with max score
    • Shortest Common Supersequence
    • Palindrome Partitioning
    • Form a Palindrome
  • Hard
    • Boolean Parenthesization
    • Matrix Chain
    • Maximum Profit
    • Minimum Cost Path
    • Partition Equal Subset Sum

  Recursion

  • Easy
    • Number of Paths
    • Pascals Triangle
    • Josephus problem
    • Tower of Hanoi
  • Medium
    • Special Keyboard
    • Flood Fill Algorithm

  Backtracking

  • Easy
    • Permutations    
  • Medium
    • Letter Combinations of a Phone Number
    • Generate Parentheses
    • Word Boggle – 1
    • Rat in a Maze Problem
    • Largest number in K swaps
    • Combination Sum
  • Hard
    • Palindrome Partitioning
    • N-Queen Problem
    • Solve the Sudoku

  Algorithms

  • Easy
    • Bubble Sort
    • Insertion Sort
    • Selection Sort
  • Medium
    • Merge Sort
    • Quick Sort
    • Heap Sort
    • Count Sort
    • Kadane Algorithm
    • Minimum Spanning Tree
    • Implementing Dijkstra Algorithm
    • Floyd Warshall
    • Bellman Ford Algorithm
    • Rabin-Karp Algorithm
    • KMP algorithm
    • Z Algorithm
    • Huffman Encoding

  Design

  • Easy
    • Stack using two queues
    • Queue using stack
  • Medium
    • Ternary Search
    • Binary Heap Operations
    • LRU cache
    • Trie | (Insert and Search)

  You may also check our latest online course series to learn DS & Algo is named DSA, which covers everything about Data Structures from Basic to Advanced.

  
   
  
  
   
  

   

  

  
  
  
  
  
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