SDE - 1

You have been given a Binary Tree of integers.

Your task is to print the Right view of it.

The right view of a Binary Tree is a set of nodes visible when the tree is viewed from the Right side and the nodes are printed from top to bottom order.

You are given a 2-dimensional array/list having N rows and M columns, which is filled with ones(1) and zeroes(0). 1 signifies land, and 0 signifies water.

A cell is said to be connected to another cell, if one cell lies immediately next to the other cell, in any of the eight directions (two vertical, two horizontal, and four diagonals).

A group of connected cells having value 1 is called an island. Your task is to find the number of such islands present in the matrix.

You are given two sorted linked lists. You have to merge them to produce a combined sorted linked list. You need to return the head of the final linked list.

Note:

The given linked lists may or may not be null.

For example:

If the first list is: 1 -> 4 -> 5 -> NULL and the second list is: 2 -> 3 -> 5 -> NULL

The final list would be: 1 -> 2 -> 3 -> 4 -> 5 -> 5 -> NULL

You are given an Integer array ‘ARR’ and an Integer ‘K’.

Your task is to find the ‘K’ most frequent elements in ‘ARR’. Return the elements in any order.

For Example:

You are given ‘ARR’ = {1, 2, 2, 3, 3} and ‘K’ = 2. 

The answer will {2, 3} as 2 and 3 are the elements occurring most times.

You are given a binary search tree of integers with N nodes. You are also given references to two nodes 'P' and 'Q' from this BST.

Your task is to find the lowest common ancestor(LCA) of these two given nodes.

The lowest common ancestor for two nodes P and Q is defined as the lowest node that has both P and Q as descendants (where we allow a node to be a descendant of itself)

A binary search tree (BST) is a binary tree data structure which has the following properties.

• The left subtree of a node contains only nodes with data less than the node’s data.
• The right subtree of a node contains only nodes with data greater than the node’s data.
• Both the left and right subtrees must also be binary search trees.

For example:

'P' = 1, 'Q' = 3
tree = 2 1 4 -1 -1 3 -1 -1 -1,

The BST corresponding will be- 

Here, we can clearly see that LCA of node 1 and node 3 is 2.