Top Most Top 15 Data Structures and Algorithm Interview Questions for Java programmer - Answers

Data structures and algorithm questions are important part of any programming job interview, be it a Java interview, C++ interview or any other programming language. Since data structures is core programming concept, its mandatory for all programmers, to know basic data structures like stack, linked list, queue, array, tree and graph. Though tree and graph are on tough side, I still see programmers to get familiar will all these. Any list of programming job interview questionsis incomplete without questions from data structures and algorithms. Similarly while going on questions from data structure you may get some programming exercise as well e.g. swapping numbers without temp variable. Linked list and arrays are favorite topics in any data structure interview, questions like reversing linked list, traversing linked list or deleting nodes from linked list, which involves algorithm and data structures are quite common. Similarly, finding duplicates in array, finding missing numbers, sorting arrays are very popular. You can also expect questions from stack, queue, array, linked list, tree, graph and HashMap are most common in any data structure interview. In this tutorial,  we will see couple of data structure questions answers from these topic. Let us know, if you have any interesting questions from data structures and algorithm, which you faced during any Java interviews.

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Top Most How to Find if Linked List contains Loops or Cycles in Java - Coding Question

Write a Java program to check if a linked list is circular or cyclic,  and how do you find if a linked list contains loop or cycles in Java are some common linked list related data structure interview questionsasked in various Java Interviews. This is some time asked as follow-up question of basic linked list questions like inserting element at beginning, middle and end of linked list or finding length of linked list. In order to solve linked list related algorithmic question in Java, you need to be familiar with concept of singly linked list, doubly linked list and circular linked list. Until stated specifically, most questions are based on singly linked list. For those who are not familiar of linked list data structure, its a collection of nodes. Each node contains two parts data and address, where address part points to another node in linked list. Last node of linked list, often referred as tail points to null. Also a singly list can only move in one direction, towards end. Now, let's come back to this question. Good thing about this question is that, it can also be solved by using two pointer approach discussed in How to find middle element of linked list in single pass. If a linked list contains a loop or cycle it is known as circular or cyclic linked list. As I said we can use two pointer approach to check if a linked list is circular or not.

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