Problems on Binary Tree

List of 50+ Binary Tree Problems for Coding Interviews

We have listed important Problems on Binary Tree which you must practice for Coding Interviews and listed introductory and background topics on Binary Tree as well. You must bookmark this page and practice all problems listed.

Algorithms

Two Sum Problem in Binary Search Tree

We have solved the Two Sum Problem in Binary Search Tree using three different approaches involving Depth First Search, Inorder Traversal and Augmented Binary Search Tree.

Algorithms

Invert / Reverse a Binary Tree [3 methods]

Inverting a binary tree is one of the most common questions asked in the interviews of many companies. In this article, we will see in detail as to how one can understand and tackle this task of inverting a binary tree using recursion, stack and queue.

Problems on Binary Tree

Implement Binary Tree in Python

We have explored the strategy to implement Binary Tree in Python Programming Language with complete explanation and different operations like traversal, search and delete.

Algorithms

Types of views in Binary tree

We have explored the different types of views of the binary tree (like Left, Right, Top and Bottom View) and discussed how to find them.

Algorithms

Convert a binary tree into its mirror tree

Given a binary tree, we have to write an algorithm to convert the binary tree to its mirror tree. A mirror tree is another binary tree with left and right children of all non-leaf nodes interchanged.

Problems on Binary Tree

Construct Binary Tree from Inorder and Preorder traversal

We present two approaches to Construct Binary Tree from Inorder and Preorder traversal. We start with background information on constructing Binary Tree from a given traversal or a set of traversals.

Data Structures

Applications of Binary Tree

Binary Tree is the most used Tree Data Structure and is used in real life Software systems. We have listed applications of Binary Tree and its variants.

Problems on Binary Tree

Level order traversal of a Binary Tree

In this article, we have explored Level order traversal of a Binary Tree in depth using two approaches: recursive approach and queue.

Algorithms

Zig Zag Traversal of Binary Tree

In this article, we present 4 different approaches for Zig Zag Traversal of Binary Tree using stack, deque, recursion and an iterative approach.

Algorithms

Check if 2 Binary Trees are isomorphic

Two Binary Trees are known as isomorphic if one of them can be obtained from the other one by series of flipping of nodes, swapping the children both left and right of number of nodes.

Algorithms

Convert Binary Tree to Circular Doubly Linked list

To convert binary tree to circular doubly linked list, we will take left node as previous pointer and right node as next pointer. The order of nodes in Doubly Linked List must be same as in inorder of the given binary tree.

Algorithms

Succinct (0-1) Encoding of Binary Tree

Succinct (0-1) Encoding of Binary Tree is an approach to encode a Binary Tree to the lowest possible space and maintain the structural information.

Algorithms

LCA in Binary Tree using Euler tour and Range Minimum Query

In this problem, we will find the Lowest Common Ancestor of a Binary Tree using Euler tour and Range Minimum Query. We can solve the LCA problem by reducing it to a RMQ problem.

Algorithms

Lowest Common Ancestor in a Binary Tree

In binary trees, for given two nodes a and b, the lowest common ancestor is the node of which both a and b are descendants. We explored the algorithm to find Lowest Common Ancestor in a Binary Tree.

Problems on Binary Tree

Operations in Threaded Binary Tree

There are three main operations which can be done on a threaded binary tree Insert, Search and Delete operation which we have explained in depth.

Problems on Binary Tree

Threaded Binary Tree

Threaded binary tree is a simple binary tree but they have a speciality that null pointers of leaf node of the binary tree is set to inorder predecessor or inorder successor.

Problems on Binary Tree

Checking if a Binary Tree is foldable

A binary tree is foldable if the left subtree and right subtree are mirror images of each other. An empty tree is also foldable. We have presented two algorithms to check if Binary Tree is foldable.

Problems on Binary Tree

Serialization and Deserialization of Binary Tree

We have presented the process of Serialization and Deserialization of Binary Tree where we convert a Binary Tree into a compress form which can be saved in a file and retrieved back.

Problems on Binary Tree

Convert a Binary Tree to a Skewed Binary Tree

We have presented the algorithm to Change a Binary Tree to a Skewed Binary Tree (both Increasing Skewed Binary Tree and Decreasing Skewed Binary Tree).

Problems on Binary Tree

Check if a Binary Tree is skewed or not

We have presented the algorithm to check if a given Binary Tree is skewed or not (can be left or right skewed Binary Tree).

Problems on Binary Tree

Introduction to Skewed Binary Tree

A binary tree can be called a skewed binary tree if all nodes have one child or no child at all. There are two types: left and right skewed.

Problems on Binary Tree

Find ancestors of a given node in a binary tree (Recursive + Iterative)

Understand how to find ancestors of a given node in a binary tree recursively and iteratively in linear time O(N).

Problems on Binary Tree

Find nodes which are at a distance k from root in a Binary Tree

We are given the root of a tree, and an integer k. We need to print all the nodes which are a distance k from the root.

Problems on Binary Tree

Find ancestors of a node in Binary tree (Recursive)

In this problem, we are given a binary tree and a key k. We need to find out all the ancestors of node k. We have used a recursive approach.