50+ Binary Tree Coding Interview Questions for Experienced Developers
60 Tree Data Structure Coding Interview Questions for Experienced Developers
Hello friends, the Tree data structure is one of the most fundamental data structure along with array and linked list in computer programming. What makes Tree unique is its ability to represent hierarchical data.
For example, you can use a tree data structure to model the Employee and Manager relationship as well as the family tree. This is not possible with arrays and linked lists because they are linear data structures. That’s why the tree data structure is quite popular in coding interviews.
Another reason why interviewers ask tree-based questions on coding interviews, like tree traversal algorithms (pre-order, post-order, and in-order), is that they are generally tougher to solve compared to array and linked list based problem, and many candidates struggle to solve tree-based coding questions.
One of the important reasons for this structure isthe lack of practice, while arrays and linked list is quite popular and everybody practice array based coding problems like reversing an array or find duplicate an array, and with linked list like reversing a linked list, and finding if a linked list contains a cycle, they are not exposed to tree-based problems so often.
But, you cannot ignore Tree data structure if you are serious about getting a technical job as a Software Developer, and that’s where you need to practice Tree-based problems on sites like LeetCode and HackerRank.
I have practiced them a lot and created my own list of tree-based problems, which I think every programmer should know how to solve, and I am sharing this list with you today. You can also solve them to not just learn Tree Data Structure better but also prepare for coding interviews
In the past, I have also shared many questions for Java developer interviews, like these 35 Java Interview Questions, Advanced Java Interview Questions, Spring Framework Interview Questions, and System Design Questions, which you can also use for practicing, as the System design topic is also quite important for interview
50+ Tree-Based Coding Problems for Interview Practice
Here is a list of popular Tree based coding questions for Software Engineer interviews. These questions not only cover basic tree implementations like Binary Tree and Binary Search Tree, but also more advanced self-balanced trees like AVL and Red Black Tree.
I have organized them in order from easy to difficult, and most importantly, they are asked on various interviews, so you will get a lot of practice.
Along the way, you will also learn key concepts about different types of tree like binary tree, binary search tree, AVL tree, Red Black Tree, and other self-balanced tree by solving these questions.
1. How to implement Tree Data Structure in Java or C++?
2. How to implement Pre-order Traversal of a Binary Tree in Java or C++?
3. Post-order Traversal of a Binary Tree in Java, Python, or C++?
4. Write a program to do In-order Traversal of a Binary Tree in Java or C++?
5. Can you write a program to implement Binary Tree Level Order Traversal in Java, Python, or C++?
6. How do you Print right view of a binary tree in Java, Python or C++?
7. Can you print all nodes of a binary tree that do not have sibling in Java?
8. How to print all Root to Leaf paths of a Binary Tree in Java or C++?
9. How to find the Minimum Depth of a Binary Tree in Java, C++, or Python?
10. How to Print left view of a binary tree in your favorite programming language? Feel free to use Java, C++, Python, Ruby, or even JavaScript.
11. How to find the sum of all left leaves of a binary tree in Java or C++?
12. How do you Find depth of the deepest odd-level leaf node in a binary tree?
13. How to check whether a binary tree is a full binary tree or not? You can use any programming language to implement this solution.
14. How to check whether a binary tree is complete or not in Java or C++?
15. How to Check if two nodes are cousins in a Binary tree in C++ and JavaScript?
16. How to check if two binary trees are identical in Java, C++, or JavaScript?
17. How to check if all internal nodes of a BST have only one child without building the tree in Java, C++, or Python?
18. How to convert the given n-ary tree to its mirror image in Java, Python, or JavaScript?
18. How to convert a binary tree to its mirror tree in Java or C++?
19. How to print top view of a binary tree in Java or C++?
20. How to Print top view of a binary tree using level order traversal in Java, C++ or Python?
21. How to print the bottom view of a binary tree in Java, Python, or C?
22. How to print the bottom view of a binary tree using level order traversal in Java or C++?
23. How to remove the nodes of a binary search tree that are outside the given range in Java or C++?
24. How to remove all nodes that lie on a path having a sum less than k in Java or C++?
25. How to remove all the half nodes from a given binary tree in Java or C++?
26. How to Print binary tree in vertical order in Java or C++?
27. How to populate right neighbors for all nodes in a binary tree in Java, Python or C++?
28. Write a Java or C++ program to find lowest Common Ancestor of two nodes in a Binary Search Tree?
29. Write a Java or C++ program to implement the iterative pre-order traversal of a Binary Tree.
30. Can you write a program to find In-order Successor of a Node in a Binary Tree in Java or the C programming language?
31. How do you recover a Binary Search Tree if positions of two nodes are swapped? Code your solution in Java, Python, or C++?
32. How do you find the floor and ceiling of an element from a given dataset using a binary search tree in Java or the C++ programming language?
33. Write a program in Java or C++ to calculate the diagonal Sum of a Binary Tree.
34. How do you create a balanced Binary Search Tree from a sorted array in Java, C++, or even JavaScript?
35. How do you convert a sorted Doubly Linked List to a Balanced Binary Search Tree in Java, C++, or Python?
36. How do you convert a binary tree to a doubly linked list in Java or C++ programming language?
36. Write a Java or C++ program to check if a binary tree is balanced or not? your program should return true if given binary tree is balanced and false if not.
37. How do you check if a binary tree is a binary search tree or not? Code your solution in Java, C++, Ruby, Python, or JavaScript programming language.
38. Write program to check if two binary search trees are identical given their array representations in Java or C++?
39. How do you check if a binary tree is a sub-tree of another binary tree in time O(n) in Java or C++?
40. Write a Java, C++, or Python program to check if a binary tree is a sub-tree of another binary tree in space O(1)
41. Write a Java or C++ program to implement Insertion, Deletion and Search operation?
42. How do you check if a given binary tree is a symmetric tree or not in Java, C, or C++ programming language?
43. How do you check if the given n-ary tree is symmetric or not in Java, Python, or C++?
44. How do you implement Spiral Level Order Traversal of a Binary Tree in Java or C++?
45. How do you find the maximum element from each sub-array of size ‘k’ in Java, Python, or C++?
46. Write a program to find total number of possible Binary Search Trees with ’n’ keys in Java, Python, JavaScript or C++?
47. How do you find the size of largest BST in a binary tree in Java or C++?
48. Write a program to find the lowest Common Ancestor of 2 nodes in a Binary Tree in Java, Python, or C++.
49. How do you find height of the binary tree from its parent array representation in Java or C++?
50. Write a Java or C++ program to convert a binary tree to a binary search tree?
51. Write a program to construct the binary tree from its parent array representation in Java or C++?
52. Write a Java or C++ program to construct binary tree from inorder and preorder traversals? Also, give their time and space complexity
53. How do you construct a binary tree from inorder and postorder traversals? Solve this problem in Java, C++, or Python
54. Implement an AVL Tree in Java or C++?
55. Implement insertion, deletion, and search in a given AVL tree in Java or C++?
56. Write a program to implement pattern matching using a trie in Java or C++?
57. Write a program to find the longest Prefix Matching using a trie in Java, C++, and Python?
58. Write a Java or C++ program that, given a sequence of words, groups together all anagrams and prints them.
59. Write a Java or C++ program serialize and deserialize a binary search tree?
60 How do you Serialize and Deserialize a binary search tree using post order traversal in Java or C++?
Java and Spring Interview Preparation Material
Before any Java and Spring Developer interview, I always used to read the following resources
Grokking the Java Interview
Grokking the Java Interview: click here
I have personally bought these books to speed up my preparation.
You can get your sample copy here, check the content of it, and go for it
Grokking the Java Interview [Free Sample Copy]: click here
If you want to prepare for the Spring Boot interview you follow this consolidated ebook, it also contains microservice questions from spring boot interviews.
Grokking the Spring Boot Interview
You can get your copy here — Grokking the Spring Boot Interview
So that’s it. These are the popular Tree Based Coding Interview Questions you can practice to not just learn Tree Data Structure better but also be ready for any kind of tree related questions on Coding Interviews.
I wish you all the best for your interviews and if you come across any other interesting tree based coding problems then you can also share with me in comments, I would love to know them.