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Problem

Submissions

Course Schedule II

Contributed by

Deep Mavani

Hard

0/120

Avg time to solve 50 mins

Success Rate 50 %

12 upvotes

Problem Statement

You have been given ‘N’ courses and some courses may have prerequisites. Now consider a matrix ‘PREREQUISITES’ of size 'M' x 2 which represents that you must complete course 'PREREQUISITES[i][1]' before the course 'PREREQUISITES[i][0]'.

Your task is to return the ordering of courses you should take to finish all courses.

Note:

If it is impossible to finish all courses, return an empty array. If there are multiple answers, return any one.

Detailed explanation ( Input/output format, Notes, Constraints, Images )

Input Format:

The first line of input contains an integer 'T' representing the number of the test case.

The first line of each test case contains an integer ‘N’ representing the number of courses.

The second line of each test case contains a given integer ‘M’ representing the number of prerequisite pairs. 

The next ‘M’ lines in each test case contain a matrix ‘PREREQUISITES’ containing two integers denoting a prerequisite pair.

Output Format:

For each test case, print a single integer 1 if the returned order of the courses is correct otherwise we return 0.

Note:

You don't need to print anything, it has already been taken care of. Just implement the given function.

Constraints :

1 <= T <= 5
2 <= N <= 100
1 <= M <= min(100,N(N-1)/2)
1 <= PREREQUISITES[i][0], PREREQUISITES[i][1] <= N

Where ‘PREREQUISITES’ denotes the prerequisites matrix.

Time limit: 1 sec

Sample Input 1:

Sample Output 1:

1
1

Explanation of Sample Output 1:

In test case 1, There are a total of 4 courses to take. To take course 4 you should have finished both courses 2 and 3. Both courses 2 and 3 should be taken after you finish course 1. So one correct course order is [1,2,3,4]. Another correct ordering is [1,3,2,4]. When the ordering is one of the above two sets then output is 1.

In test case 2, There are 3 courses to take. To start with, First course 3 is taken. Then course 2 is taken for which course 3 must be completed. At last course 1 is taken for which course must be completed. So correct course order is [3,2,1].

Sample Input 2:

Sample Output 2:

1
1

Explanation of Sample Output 2:

In test case 1, there are a total of 2 courses to take. To take course 2 you should have finished course 1. So the correct course order is [1, 2]. Ordering [1, 2] is correct.

In test case 2, there is only one course and so no pairs of courses are possible and thus the only correct order of courses is [1].

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