We have once again compiled a list of must-do coding questions for product-based companies. A must-read for anyone looking to crack the interview of technology-based firms.

Getting into top product-based companies can be very tough even for talented learners. For instance, when applying for companies like Google and Microsoft, acing an interview is the key.

Many people have failed to secure a position in top product-based companies because of poor interview performance. Today we will cover some of the must-do coding questions for interviews across topics.

Over the past few years, trends have shown that the most important topics for interviews in product-based companies focus on Data Structures and Algorithms.

Since Data Structures and Algorithms tell a lot about how competent a candidate is, being thorough in these fields is crucial. So, let’s find out more about the topics to focus on and the questions to keep note of.

Must Do Coding Questions for Product Based Companies


Some of the most common topics for interviews at product-based companies include arrays, strings, recursion and backtracking; linked lists, stacks and queues— as well as binary trees.

Priority queues are also important to know about when applying to work with databases or other sorts of large collections.

While providing a comprehensive list of questions is beyond our scope, we will try to address the issues important for most readers.

Please note that this is not an exhaustive list and it’s not a good idea to rote learn only a specific set of questions for interviews:


Arrays are linear data structures with a predetermined size, which store elements in contiguous memory blocks. ‌A multidimensional array can contain more than one element.

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Matrices are one of the best applications for multidimensional arrays, which need to be studied separately.

The following topics under arrays are important for product-based company interviews:

  • Pair Sum
  • Overlapping Intervals
  • Sort 0 1 2
  • Search In Rotated Sorted Array
  • Smallest Subarray With K Distinct Elements
  • Other Questions Practice Link
  • Search In Row Wise And Column Wise Sorted Matrix
  • Inplace Rotate Matrix By 90 degree
  • Matrix Median


Strings are arrays that contain characters as‌ ‌their elements. They differ from character arrays in that they end with the‌ symbol ‘\0’.

The following topics related to strings are essential for interviews in product-based companies:

  • Longest substring without repeating characters
  • Anagram Difference
  • Shortest substring with all characters
  • Minimum operations to make strings equal
  • Left And Right Rotation Of A String
  • Shortest substring with all characters
  • Next smaller Palindrome
  • Longest Substring Without Repeating Characters
  • Anagram Difference
  • Match Specific Pattern
  • Minimum operations to make strings equal
  • Find K’th Character of Decrypted String
  • Anagram Substring Search

Linked Lists

Data structures such as Linked Lists make up dynamic linear data structures that have nodes where each node contains two fields of information: data and a pointer to the next node.

In a single linked list, the first node points to the second node, and so on. In a doubly-linked list, the second node points to the third node, and so on.

Questions from the following topics are essential for interviews:

  • Merge Two Sorted Linked List
  • Detect And Remove Loop
  • Reverse List In K Groups
  • Intersection Of Two Linked Lists
  • Sum Between Zeros
  • Reverse List in K groups
  • Sum Between Zeroes
  • Rearrange Linked List
  • Clone Linked List with Random Pointer
  • Merge Two Sorted Linked Lists
  • Detect and Remove Cycle
Also Read:  10 Basic C++ Questions to Ease Your Interview Prep

Recursion & Backtracking

In programming, recursion occurs when a function is called by itself directly or indirectly. Recursion is a technique in programming in which a function is called by itself directly or indirectly.

This allows complex problems to be broken down into smaller ones. Alternatively, backtracking is solving a problem by iterating through a series of smaller levels of the problem until one reaches the goal.

These topics from recursion and backtracking are essential from an interview perspective:

  • Print Permutations Of String
  • Return Subsets Sum to K
  • Sudoku
  • Replace ‘O’ with ‘X’
  • Reach Destination
  • Reach the destination
  • Reverse Stack Using Recursion
  • K subsets with an equal sum
  • Minimum distance points
  • Print Permutations – String
  • IP Address
  • Replace ‘O’ with ‘X’
  • Return Subsets Sum to K
  • Binary strings with no consecutive 1s

Binary Trees

Binary Trees consist of at least two children for every node. ‌Every node consists of three fields—data, a pointer to a child on the left, and a pointer to a child on the right.

Here are some must-do coding questions for product-based companies for interviews in Binary Trees:

  • Binary Tree From Parent Array
  • Maximum Sum Path From Root To Leaf
  • Print Node At Distance K From Given node
  • Maximum Width In Binary Tree
  • Time To Burn Tree
  • Binary Tree from Parent Array
  • Print Leaf Nodes
  • Diagonal Anagram
  • Maximum sum path from the leaf to root
  • Print Nodes at a distance K from a given node
  • LCA of three Nodes
  • Count elements in all subtrees
  • Maximum Width In Binary Tree
  • Count Special Nodes in Generic Tree

This guide is just an introduction to what types of questions you should target to ace interviews in product-based companies. For more interview tips and strategies, head over to the CodeQuotient blog.

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