SDE - 1

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 have been given an integer array/list(ARR) of size 'N'. It only contains 0s, 1s and 2s. Write a solution to sort this array/list.

Note :

Try to solve the problem in 'Single Scan'. ' Single Scan' refers to iterating over the array/list just once or to put it in other words, you will be visiting each element in the array/list just once.

Given a singly linked list, you have to detect the loop and remove the loop from the linked list, if present. You have to make changes in the given linked list itself and return the updated linked list.

Expected Complexity: Try doing it in O(n) time complexity and O(1) space complexity. Here, n is the number of nodes in the linked list.

You are given an array(PRICES) of stock prices for N consecutive days. Your task is to find the maximum profit that you can make by completing as many transactions as you like, where a transaction denotes buying one and selling one share of the stock.

Note:

You must sell the stock before you buy it again.

You have been given a Binary Search Tree of integers. You are supposed to return the k-th (1-indexed) smallest element in the tree.

For example:

For the given binary search tree and k = 3

The 3rd smallest node is highlighted in yellow colour.   

He started asking DBMS questions like joins , Relational models , and many more

There are two gates, one to hell and the other to heaven. Two gatekeepers, one for each gate. One of them always speaks the truth and the other always lies but you don’t know which one guards which gate. You are allowed only one question and you need to find out the gate to heaven.
What is the question?

You are given two strings 'S' and 'T' of lengths 'N' and 'M' respectively. Find the "Edit Distance" between the strings.

Edit Distance of two strings is the minimum number of steps required to make one string equal to the other. In order to do so, you can perform the following three operations:

1. Delete a character
2. Replace a character with another one
3. Insert a character

Note:

Strings don't contain spaces in between.