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DataStructures Interview Questions

1. Reverse a Linked List - LinkedListReversal.java
2. Get Square Root of a given number - SquareRoot.java
3. Count Occurance of a given number in sorted array - SortedOccurenceCounter.java
4. Finding GCD of two numbers - GCDFinder.java
5. Print all valid combinations of groups of parenthesis - ParenthesisCombinationPrinter.java
6. Convert a double number to rational - DoubleToRational.java
7. String Permutation - PrintAllStringPermutations.java
8. Find the 1st index of a given number in a sorted array allowing duplicates - IndexInSortedArray.java
9. Verify if a binary tree is a Binary Search Tree (BST) - BSTVerifier.java
10. Print BTree in pre order, post order, in order and level order - BTreeTraversal.java
11. Verify if a string is a rotated palindrome - RotatedPalindrome.java
12. Print all pairs in a sorted array that sum to M - PairsWithSumFinder.java
13. Use stack (LIFO) to simulate queue (FIFO) - QueueWithStack.java
14. There are two sorted arrays. First one is of size m+n containing only m elements. Another one is of size n and contains n elements. Merge these two arrays into the first array of size m+n such that the output is sorted - SortedArraysMerger.java
15. Verify if strings are rotations of each other or not - RotatedString.java
16. To design a tiny URL or URL shortener - ShortURLGenerator.java
17. Write a Pseudo code to parse a String and and evaluate expressions - StringExpressionEvaluator.java
18. Code to find number of ways to cover n stairs when you can take 1 or 2 step at a time - StairwayClimbWaysFinder.java
19. Generic implementation of BlockingQueue - BlockingQueue.java
20. Simple thread pool implementation in Java - ThreadPoolManager.java
21. Merge an array of size n into another array of size m+n - MPlusNArrayMerge.java
22. Given a number n, print all primes smaller than or equal to n - PrimeNumberPrinter.java
23. Print BTree is spiral order - BTreeTraversal.java
24. Given an array of positive integers, arrange the numbers to form the largest possible number - FormLargestNumber.java
25. Give a circle with center (0,0) and a radius r (integer > 0), find the number of points (x,y) on the circumference such that x and y both are integers - IntegralPointsOnCirle.java
26. Find if a given Singly Linked list is a palindrome or not - LinkedListPalindromeFinder.java
27. Print even and odd numbers in order using two threads - PrintOddEven.java
28. Find the middle element of a linked list - LinkedListMidFinder.java
29. Find the Lowest Common Ancestor (LCA) of two nodes in a Binary Tree - LCAFinder.java