Top Coding Interview Questions for Software Engineers
Coding interviews at the best tech companies are highly competitive and arduous to crack. They can put you to the test even if you’re an experienced programmer. To ace coding interviews at FAANG+ companies, you need to be a great problem solver.
You need to diligently devote yourself to solving as many coding interview questions as possible. The questions we’re referring to here are problem-based questions in core data structures and algorithms. The problems asked at interviews are sometimes significantly challenging, meaning that if a solid strategy isn’t in place, you’re unlikely to make the cut.
The reason that FAANG+ companies ask tricky core DSA problems in coding interviews is to hire engineers who can find tech solutions to real-world problems through their fundamental ability to use programming and software to create solutions.
"Programs must be written for people to read and only incidentally for machines to execute."- –Harold Abelson
(Computer Scientist and Author)
Knowing how to solve tricky coding interview questions requires dedicated effort backed by a good, sound strategy. To help you prepare for your next coding interview, we’ve compiled this list of the most common coding interview questions asked at FAANG+ interviews. These coding interview questions are around various topics fundamentally pertaining to core data structures and algorithms.
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Let’s go ahead and look at some common coding interview questions to help you ace your next technical interview:
- Coding Interview Questions on Arrays
- Coding Interview Questions on Strings
- Coding Interview Questions on Linked Lists
- Coding Interview Questions on Trees and Graphs
- Java and Python Coding Interview Questions
- FAANG Coding Interview Questions
- FAQs About Coding Interview Questions
Coding Interview Questions: Topics to Prepare
To crack coding interviews at FAANG+ companies, it is important to know what topics to prepare. Below is the list of topics to cover in order to be able to solve coding interviews at FAANG+ companies.
- Arrays, strings, and linked lists
- Sorting algorithms — quicksort, merge sort, heap sort, etc.
- Hash tables and queues
- Trees and graphs
- Graph algorithms, including greedy algorithms
- Dynamic programming
For a comprehensive checklist of all coding interview topics you should prepare, check out the technical interview checklist.
Coding Interview Questions on Arrays
Here are some sample coding interview questions on Arrays:
- Given an unordered array of integers, write a program that finds a contiguous subarray whose sum is equal to the given one.
- For two unsorted arrays in ascending order, write a code to merge them such that the new array is in ascending order.
- For a given array having values from 1 to N and the first array containing the element at every position in the second array, write a program that finds the position of the missing element in the second array.
- For a given array of positive integers, write a code that computes the sum of the elements.
- For a given unsorted array of size N, write a function to rotate it by D elements anticlockwise.
- For a given sequence of size N, determine a code to print the original sequence.
- Write a function to locate and delete duplicate elements from an ordered array.
- For a given 2D array containing integer elements, write code to find the minimum length and maximum length.
Coding Interview Questions on Strings
Following are some coding interview questions on strings that you can practice for your upcoming tech interview.
- Consider any String S and write code to reverse the string S without disturbing the individual words.
- Given a text string, write a program that returns all the permutations.
- Write a program that returns the longest palindrome substring of a given string.
- For a given String that has elements represented in Roman numerals (A=1, etc.), write a code to convert the String into Roman numerals.
- Write a program that will delete duplicate letters from a string.
- Write a code to convert a given string into a palindrome.
- Write a code to find the longest subsequence of a string with distinct items in it.
- For a given string S: write code to remove successive identical characters recursively.
Coding Interview Questions on Linked Lists
Questions on linked lists are pretty common at tech interviews at top companies. Here are a few sample questions to get you started:
- How to insert a node at the end of a Linked List
- How do you remove a particular node from a Linked List?
- Write a function to reverse a singly linked list
- Add two numbers represented by linked lists
- Write a recursive function to remove the nth node from a Linked List.
- Write a function to move nodes in a link list by swapping adjacent nodes
- Write a code that will invert the values of an array at a specific point
Coding Interview Questions on Trees and Graphs
Trees and Graphs are crucial topics for tech interviews. Here are some sample coding interview questions:
- You are given a binary tree where each node contains a positive integer. Find the maximum sum that can be found over a path from one node to the other.
- For a given binary tree: Calculate its height.
- For any given binary tree, which contains all unique values, write a code to find the lowest common ancestors of the nodes of the tree.
- How to connect nodes that have the same vertical distance
- For a given binary tree T, a function finds its level-order traversal
- To trace the vertical traversal of a given binary tree, write a program that outputs the tree.
- Write a program to print the bottom view of a binary search tree as you scroll left to right.
- You're given the root of a binary tree T. Write a program that will tell you whether it is a binary search tree or not.
Coding Interview Questions on Java and Python
Java and Python are the most common programming languages that are used by programmers at coding interviews. Apart from testing your knowledge of core data structures and algorithms, hiring managers also evaluate your understanding of core OOP concepts in these languages.
We’ll look at some sample coding interview questions in Java and Python to help you prepare for your next coding interview!
Java Coding Interview Questions
If you’re a Java developer, Java coding interview questions at technical interviews are mostly around core Java concepts and framework environments.
Below are some sample Java coding interview questions:
- Write a program to check if two 2-dimensional arrays contain identical elements
- From a given set of strings, write a function to determine which string has the highest number of vowels
- Write a program to reverse the characters in a string
- Write a program to implement binary search in Java
- For a given set of employees and their age, write a program to sort the employee names from youngest to oldest.
To access more Java coding interview questions, check out the Java Interview Questions page.
Python Coding Interview Questions
Python is one of the most widely used programming languages by developers to solve complex coding and data problems. If you’re preparing for technical interviews, it is crucial that you know how to solve core DSA and algorithm problems using Python.
Below are some sample Python coding interview questions to practice for your next coding interview:
- Write a program to return a specific node in a doubly linked list.
- Write a code to count the number of strongly connected components in a binary search tree.
- Write a program to determine the inversion count for a given 2-dimensional array.
- Write a program to print the heights of multiple binary trees and return the binary tree with the highest height.
- Write a code to connect the nodes of a binary tree that are at the same level.
Visit our Python Interview Questions for more such coding problems.
Coding Interview Questions at FAANG
Coding interview questions are a crucial part of FAANG interviews. Questions and problems asked at these interviews are typically in the range of medium to hard on Leetcode. Practicing as many coding problems is absolutely crucial if you wish to set yourself apart from the competition.
More than practicing a certain number of problems, it is important to identify patterns in solutions and use similar patterns to solve new problems.
Let’s look at some popular coding interview questions asked at top companies to help you understand the type of problems to expect at FAANG coding interviews.
Google Coding Interview Questions
Google has a notoriously competitive interview process that filters in barely 2% of engineers who apply. Google’s coding interview essentially evaluates your knowledge of core data structures and algorithms.
Let’s take a look at some sample Google coding interview questions:
- Write a program to merge two sorted arrays, A and B.
- For a given array containing integer elements in a set sequence and one element out of sequence, write a program to find the element.
- Write a code to implement Breadth-First Search.
- Write a program to convert a binary tree into a doubly linked list
- Write a program to find the shortest path that can be traversed between two graph nodes.
For more Google-specific coding interview questions, check out the Google Coding Interview Questions page.
Amazon Coding Interview Questions
Just like Google, Amazon also has a reputation for an interview process that’s extremely challenging and hard to crack. The Amazon software developer interview has multiple coding rounds where hiring managers evaluate your core problem-solving and programming capabilities.
Below are some sample Amazon coding interview questions:
- Write a program to rotate an unsorted array of size “S” clockwise.
- Write a program to find the index-based distance between two elements of a given 2-dimensional array.
- Write a code to calculate the median of the elements in a given one-dimensional sorted array.
- Write a program to convert the last letter of a given set of strings into uppercase.
- Write a program to reverse individual characters in a set of strings without reversing the words.
Check out some additional Amazon Coding interview questions on the Amazon Coding Interview Questions page.
Facebook Coding Interview Questions
Facebook’s technical interview comprises 2-3 coding interview rounds, where hiring managers specifically aim to evaluate your approach to problem-solving and how you’re able to articulate problem solutions effectively. Practicing as many coding problems as possible is key to cracking Facebook’s technical interview.
Let’s look at some sample Facebook coding interview questions:
- Write a program to print only the left view of a given binary tree.
- Write a program to remove duplicate elements in a given string.
- Write a code to implement Tarjan’s Greedy algorithm. To perform BFS.
- Write a function to implement a queue using two stacks.
- Write a program to find the maximum path sum for a non-empty binary search tree.
Check out the Facebook Coding Interview Questions page to access several more coding questions asked at Facebook’s interview.
Practicing these above coding interview questions can help you tackle challenging problems at FAANG+ technical interviews.
FAQs About Coding Interview Questions
Q1. What topics should you prepare to solve coding interview questions in a technical interview?
To solve data structures interview questions, you must be thorough with the following concepts - arrays, strings, linked lists, recursion, hash tables, graphs, trees, and dynamic programming.
Q2. How many coding interview rounds are there in FAANG interviews?
Interviews at FAANG companies typically have 2-3 coding interview rounds. The first two rounds are usually technical screening rounds.
Q3. How long should you ideally prepare for FAANG coding interviews?
As a rule of thumb, it is crucial that you start preparing for your coding interview at least 6 weeks before your interview.
Q4. Are coding interview questions asked at domain-specific tech interviews?
Yes, most domain-specific tech interviews, such as ML interviews, testing interviews, cloud interviews, and web developer interviews, have mandatory coding rounds where your knowledge of programming concepts, core data structures, and algorithms is evaluated.
Q5. How long do coding interview rounds last at FAANG companies?
Coding interview rounds typically last 30-40 minutes. Recruiters mostly aim to evaluate your approach to problem-solving and your ability to write error-free code.
Q6. What is the difference between coding and programming?
Coding is the process of writing code in a particular programming language. It entails converting human-readable commands into a computer-executable representation. Writing functions, classes, and algorithms are examples of such chores.
Programming is a larger term that includes coding. It involves developing algorithms, problem-solving, and a set of instructions for a computer to follow in order to complete a given task. Programming includes not just developing code but also planning, testing, debugging, and maintaining code.
Q7. Can one Google during a HackerRank test?
It is quite acceptable to use Google when working on hackerRank unless you try to steal from it.
Get Ready for Your Upcoming Technical Interview
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