SDE - Intern

A Directed Acyclic Graph (DAG) is a directed graph that contains no cycles.

Topological Sorting of DAG is a linear ordering of vertices such that for every directed edge from vertex ‘u’ to vertex ‘v’, vertex ‘u’ comes before ‘v’ in the ordering. Topological Sorting for a graph is not possible if the graph is not a DAG.

Given a DAG consisting of ‘V’ vertices and ‘E’ edges, you need to find out any topological sorting of this DAG. Return an array of size ‘V’ representing the topological sort of the vertices of the given DAG.

For example, Consider the DAG shown in the picture.

In this graph, there are directed edges from 0 to 1 and 0 to 3, so 0 should come before 1 and 3. Also, there are directed edges from 1 to 2 and 3 to 2 so 1 and 3 should come before 2.

So, The topological sorting of this DAG is {0 1 3 2}.

Note that there are multiple topological sortings possible for a DAG. For the graph given above one another topological sorting is: {0, 3, 1, 2}

Note:

1. It is guaranteed that the given graph is DAG.
2. There will be no multiple edges and self-loops in the given DAG.
3. There can be multiple correct solutions, you can find any one of them. 
4. Don’t print anything, just return an array representing the topological sort of the vertices of the given DAG.

You are given two strings 'A' and 'B' of length 'N' and 'M' respectively, your task is to find the number of distinct occurrences of string 'B' in the string A as a subsequence.

Note:

1. A subsequence is a sequence generated from a string after deleting some characters of string without changing the order of remaining string characters.

2. 'A' and 'B' will be non-empty strings.

You are given two Singly Linked Lists of integers, which may have an intersection point.

Your task is to return the first intersection node. If there is no intersection, return NULL.

Example:-

The Linked Lists, where a1, a2, c1, c2, c3 is the first linked list and b1, b2, b3, c1, c2, c3 is the second linked list, merging at node c1.