Practicing Java algorithms interview questions is essential for any Java interview preparation. The data structure and algorithm interview questions can be solved in multiple languages but sometimes involve questions that target a specific language. This article will go through some Java algorithm interview questions to assist you in preparing for your upcoming coding interviews.
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In this article, we’ll learn:
While thorough preparation is essential, ensuring that you are well-versed in some key topics is a useful checklist to have. The important data structures and algorithm topics are:
You can check out more relevant articles like Stability in Sorting Algorithms and Time and Space Complexities of Sorting Algorithms Explained on Interview Kickstart’s learn page.
Let’s take a look at some popular Java algorithms interview questions that you can practice for your tech interview:
Q1. What are the different types of tree traversal algorithms?
There are broadly four types of tree traversals, and each type has algorithms that help us achieve that type of traversal. The four types are inorder traversal, preorder traversal, postorder traversal, and level order traversal.
Q2. What are some of the most used sorting algorithms?
This is a commonly asked Java algorithms interview question. It tests your basic conceptual knowledge. Here’s how you can answer this: Quicksort, merge sort, heap sort, and insertion sort are some of the most used sorting algorithms.
Q3. What are some examples of greedy algorithms?
Travelling Salesman problem, Knapsack problem, job scheduling problem, Prim's, Kruskal's, and Dijkstra's Minimum Spanning Tree algorithms, Map coloring in Graphs, and Vertex cover in graphs are some examples that utilize greedy algorithms.
Q4. Give some examples of divide and conquer algorithms.
Binary Search, Merge Sort, Quick Sort, and Strassen's Matrix Multiplication are some examples of divide and conquer algorithms.
Q5. What is the fastest searching algorithm?
Binary search is usually the fastest searching algorithm and is most widely used for efficient searching as well.
We’ll now look at some basic Java algorithm coding interview questions for freshers that you should definitely practice to ramp up your preparation. Let us jump right in!
Q1. How would you:
Q2. How would you find:
Q3. Given a sorted array and a number N, find the pair in the array whose sum is closest to N.
Q4. Given an array containing zeroes, ones, and twos only, sort the array with an algorithm that gives O(n) time complexity.
Here are some more frequently asked Java algorithms interview questions for experienced developers to help you be sure of your interview preparation:
Q1. How would you find:
Q2. How would you:
Q3. Write a program to check if a string:
Q4. Implement a stack using:
Q5. In a linked list, how would you find:
Q6. For a binary tree, write an algorithm to do:
Q7. For a binary search tree, how would you:
Q8. How would you convert the following into a balanced binary search tree:
Q9. Implement the following sorting algorithms in Java:
Q 10. Print:
Q11. Implement the following algorithms in Java:
Q1. What algorithms should I know for Java interviews?
You should definitely know algorithms with low time complexity, like O(1), O(logN), and O(N*logN), that also don’t take up too much space for your Java interviews. More importantly, you should know how to implement them.
Q2. Why are algorithm questions asked in interviews?
Algorithms are a crucial part of any software development process. An efficient algorithm can run for millions of users in a short time, taking little space and using only a reasonable amount of system resources. An inefficient or inaccurate algorithm can break, cause a company a significant loss, and wastes time, space, and other system resources. Hence, algorithm skills are important in interviews.
Q3. What makes an algorithm greedy?
An algorithm that uses the strategy of making the most optimal choice at each small step with the hope that this will eventually lead to a globally optimal solution is a greedy algorithm.
Q4. What are some different types of algorithms?
Simple recursive, backtracking, divide and conquer, dynamic programming, greedy, branch and bound, brute force, and randomized algorithms are some different types of algorithms.
Q5. What are five things algorithms must possess?
The five things algorithms must possess are definiteness, inputs, outputs, finiteness, and effectiveness.
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