Cracking an interview successfully is a complete process and the most important part of this process is preparing yourself for the interview. 

When it comes to coding interviews, there are a lot more concepts to go through than you have anticipated. This is what makes it a bit tough to crack. However, going through all concepts in detail is not possible for anyone. 

Therefore, revising and understanding only the important and generally asked concepts is the perfect way to clear your interview with ease. Here, we have come up with a complete list of tree interview questions and practice problems to help you ace questions related to binary trees.

So, let’s get started with all the common binary tree interview questions and their solutions!

Top Interview Questions And Practice Problems

1. What is a binary tree?

It is like a tree structure whose every node can have a maximum of two children. They are also known as the right and the left child respectively. Moreover, the uppermost node of the binary tree is also known as the root node.

2. How many types of a binary tree are there?

There are three types of binary trees in programming. They are

• Full tree: In this tree, all the nodes except the leaf node will have two children.

• Complete Tree: In this type of tree, the whole tree is complete except the last node.

• Perfect Tree: In this type of tree, each node will have two children and every node is at an equal level.

3. How to find the height of the binary tree?

Here, you will be provided with a binary tree and then you will have to find the height of the tree. To find the height of the tree, you can either use a recursion method or level order traversal method. Begin traversing the tree from the root and storing the elements in the queue to check the height of the tree.

4. How to check if two trees are identical or not?

The given trees are identical if they contain the same values and the arrangement of those values is also the same. To check if the trees are identical, you will have to traverse both the given trees simultaneously and also, compare the data values of both the trees and their children.

5. How to construct a binary tree from the given parent array?

This is one of the medium-level tree interview questions that you will encounter in an array. Here, you will have an array consisting of all the indexes of an array that will represent the nodes of the tree. Moreover, the value of the array will be given a parent node of that index. The index of the root node will be -1 because the root node will have no parent node.

To construct the tree, you can use different methods. Either you can simply search the present node and look for the recurring indexes or you can use a temporary data structure to store the data.

6. How to construct a binary search tree using a sorted linked list?

Here, you will be provided with a singly linked list whose all the members are sorted in ascending order. You will now have to construct a binary search tree with the members of the given linked list. To construct a binary search tree, you will have to find the middle element and make it the root node to construct the tree. 

7. How to merge two binary search trees?

Merging the two binary search trees is one of the questions asked in many interview questions. In this question, you will be given two binary trees and you need to print the elements of these binary trees in sorted order. To merge two binary trees, you will have to use two stacks and compare the values to store them in sorted order. However, there are methods also like recursion or iterative method but they are more time and space-consuming.

8. What is the largest binary search tree problem?

In this problem, you will be given a binary tree. In the binary tree, you will have to look for a subtree which is the largest and is itself a binary tree. One thing that you have to consider here is that the size is defined as the number of nodes the tree has. To find the largest binary search tree, we need to check in case the largest data of your left subtree is lower than that of your root node or in case the smallest value of your right subtree is larger than your root node.

9. Explain the children's sum parent problem.

In the children sum parent problem, you will have a binary tree and you will have to check if the value of all nodes is equal to the total of the values in child nodes. To check if the tree fulfils the children sum parent property, you will have to use the recursion method. 

In this method, you will have to consider each node separately and check if it fulfils the property or not.

10. How to find the Kth largest element in the binary search tree?

Another very basic yet important tree interview question is finding the largest kth element in the given binary search tree. Here, you will have to write a code to return the largest value present in the binary search tree without performing any modifications in the tree. 

To find the kth largest element, you will have to perform the reverse traversal of the given array and when the kth index is traversed, the process is stopped and the value at the kth index is printed. 

Conclusion

The binary tree itself is an extensive topic and it may take a lot of time for a programmer to revise each and every operation and problem related to it. This is why it is beneficial to go through generally asked questions and master them.

Keeping that in mind, we have listed and solved all the generally asked binary tree interview questions for you. These questions can also be asked as Uber Coding questions. 

Check out the related solutions as well to make the revision process simpler.