SDE - Intern

The gardener wants to water the garden by opening the minimum number of taps. The garden is one-dimensional along the x-axis of length N i.e. the garden starts from point 0 and ends at point N. There are N + 1 tap located at points [0, 1, 2, …, N] in the garden.

You are given an integer N, and an array named “ranges” of size N + 1(0-indexed). The ith tap, if opened, can water the gardener from point (i - ranges[i]) to (i + ranges[i]) including both. The task is to find the minimum number of taps that should be open to water the whole garden, return -1 if the garden can not be watered.

Example :

Follow Up:

Can you solve the problem in O(N) time?

You are given two linked lists L1 and L2 which are sorted in ascending order. You have to make a linked list with the elements which are present in both the linked lists and are present in ascending order.

Example:-

L1 = 1->2->3->4->7
L2 = 2->4->6->7

ANSWER:- The answer should be 2->4->7 because 2,4, and 7 are present in both the linked lists.

You are given a Singly Linked List of integers. Return true if it has a cycle, else return false.

A cycle occurs when a node's next points back to a previous node in the list.

Example:

In the given linked list, there is a cycle, hence we return true.

Write a SQL query: Employee and department table is given you need to find the salary of employees in each department
Which databases have you used? 
Difference between SQL and NoSQL?
What is the CAP theorem?

Given a directed acyclic graph having ‘N’ nodes. A matrix ‘edges’ of size M x 2 is given which represents the ‘M’ edges such that there is an edge directed from node edges[i][0] to node edges[i][1].

Find the smallest set of vertices from which all the nodes in the graph are reachable.

Note :

Nodes are numbered from 0 to N - 1.

The graph given is connected.

Print the vertices in sorted order.

For Example :

The following is an example of DAG i.e a directed graph with no cycles in it. 

In the above graph, we can reach all the vertices from node a.