Introduction
This is the seventh article in the Tree Traversals - Online Classes.
This article presents ways to find out inorder predecessor of node in binary tree. As we have already read about the Inorder Successor it wont take much effort to understand the predecessor.
Definition - Inorder Predecessor of node in Binary Tree
If a node K is called the inorder predecessor of node N then N must be visited immediately after K in a inorder traversal of the tree.
Below is a more formal definition of Inorder Predecessor:
If the node has a left sub-tree, then inorder predecessor is the ...

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# Algorithms

This category contains all the posts related to Algorithms. For e.g.: Sorting, Hashing, Searching, Tree Traversals, Graph Theory etc.

## Inorder Successor of node in Binary Tree Using Parent Pointer

Introduction
This is the sixth article in the Tree Traversals - Online Classes.
This article presents ways to find out inorder successor of node in binary tree. Before we jump into the code it would be good to correctly define the meaning of the problem.
Definition - Inorder Successor of node in Binary Tree
If a node K is called the inorder successor of node N then K must be visited immediately after N in a inorder traversal of the tree.
Below is a more formal definition of Inorder Successor:
If the node has a right sub-tree, then inorder successor is the left most node of the rig...

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## Tree Diameter

Introduction
This is the fifth article in the Tree Traversals - Online Classes.
A very interesting problem is to find the diameter of a tree. The challenge is not in coding the algorithm but in understanding the meaning of the problem. We will try to define the problem so that visualizing the solution becomes easy.
Defining the problem - Tree Diameter
Few confusions about the diameter must be avoided before we start.
The tree diameter is always the distance between two leaf nodes
The diameter may or may not pass through the root.
The diameter can also lie on one of the two sides,...

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## Spiral Traversal

Spiral Traversal or Zigzag Traversal in a Tree.
This is the fourth article in the Tree Traversals - Online Classes.
Recently I wrote an article on Level Order Tree Traversal. Another problem on the same lines is to traverse the tree in a zigzag manner. That is also termed as spiral traversal. This question has been asked in many companies during the interview process.
Although it is not very specific problem, if you understand the idea behind traversing a tree in breadth first manner, then you can easily solve this. Please read further for more understanding.
Defining the problem
L...

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## Level Order Tree Traversal

Introduction
This is the third article in the Tree Traversals - Online Classes.
I have written many articles about non-linear data structures and their traversals. But the more you dive in you can find many more ways to traverse a tree. Here we try to solve the level order tree traversal for a binary tree and we will also try to figure out other variations of this traversal. This can we precisely extended for a n-ary tree as well.
Defining the problem
Let us consider the above tree, if we follow the blue line from root till end and print all the nodes, we will end up printing the lev...

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