SDE - 1

Given a string input of length n, find the length of the longest substring without repeating characters i.e return a substring that does not have any repeating characters.

Substring is the continuous sub-part of the string formed by removing zero or more characters from both ends.

Given a binary tree of integers, you are supposed to modify the given binary tree to a sum tree where each node value is replaced by the sum of the values of both left and right subtrees in the given tree. The value of leaf nodes is changed to zero.

Example:

Below is the example showing the input tree and its sum tree.  

You are given a binary tree, where the data present in each node is an integer. You have to find whether the given tree is symmetric or not.

Symmetric tree is a binary tree, whose mirror image is exactly the same as the original tree.

For Example:

You are given a Binary Tree ‘root’. The given Binary Tree may or may not be a Binary Search Tree(BST) itself. Your task is to find the maximum sum of node values of any subtree that is a Binary Search Tree(BST).

Binary Search Tree is defined as follows:

1) If the left subtree exists it should contain only nodes with values less than the current node's value.

2) If the right subtree exists it should contain only nodes with values greater than the current node's value.

3) Both the left and right subtrees should also be Binary Search Tree.

Example :

For the above binary tree, the BST with the maximum possible sum is marked with RED colour, the sum of this BST is equal to 6.

You are given the ‘root’ of a Balanced Binary Search Tree and an integer ‘target,’ you have to tell if there exists any pair of nodes such that the sum of their value is equal to the target.

More formally check if there exist any two distinct nodes, whose sum is equal to ‘target.’

Note:

A binary search tree, also called an ordered or sorted binary tree, is a rooted binary tree whose internal nodes each store a key greater than all the keys in the node's left subtree and less than those in its right subtree.

A balanced binary search tree is a tree in which each node has either 0 or 2 children.

Example:

For Example, the root node is given as follows :
‘ROOT’ = 5 2 6 -1 -1 -1 -1 and ‘target’ = 8, The answer will be true since the sum of both leaf nodes is equal to 8.

Given a Binary Search Tree (BST) and a range [min, max], remove all keys which are outside the given range. The modified tree should also be BST.