SDE - Intern

Given a binary tree, convert this binary tree into its mirror tree.

A binary tree is a tree in which each parent node has at most two children.

Mirror of a Tree: Mirror of a Binary Tree T is another Binary Tree M(T) with left and right children of all non-leaf nodes interchanged.

Note:

1. Make in-place changes, that is, modify the nodes given a binary tree to get the required mirror tree.

How would you implement undo and redo operations for ms word?

You have been given a Binary Tree of 'n' nodes, where the nodes have integer values

Print the left view of the binary tree.

Example :

If the input tree is as depicted in the picture: 

The Left View of the tree will be:  2 35 2 

Implement a Trie Data Structure which supports the following three operations:

Operation 1 - insert(word) - To insert a string WORD in the Trie.

Operation 2-  search(word) - To check if a string WORD is present in Trie or not.

Operation 3-  startsWith(word) - To check if there is a string that has the prefix WORD.

Trie is a data structure that is like a tree data structure in its organisation. It consists of nodes that store letters or alphabets of words, which can be added, retrieved, and deleted from the trie in a very efficient way.

In other words, Trie is an information retrieval data structure, which can beat naive data structures like Hashmap, Tree, etc in the time complexities of its operations.

The above figure is the representation of a Trie. New words that are added are inserted as the children of the root node. 

Alphabets are added in the top to bottom fashion in parent to children hierarchy. Alphabets that are highlighted with blue circles are the end nodes that mark the ending of a word in the Trie.

For Example:-

Type = ["insert", "search"], Query = ["coding", "coding].
We return ["null", "true"] as coding is present in the trie after 1st operation.