Problem Description

Given a graph with 'N' nodes and 'M' unidirectional edges, along with two integers 'S' and 'D' representing the source and destination respectively, your task is to find all possible paths from 'S' to 'D'.

Explanation:

An ordered sequence of nodes { S, u1, u2...un, D } is considered a valid path between 'S' and 'D' if all nodes in the path are unique.

Input:

The first line contains one positive integer 'T', denoting the number of test cases. For each test case:
 - The first line contains two integers 'N' and 'M', indicating the number of nodes and the number of edges respectively.
 - The next 'M' lines each contain two space-separated integers 'u' and 'v', denoting an edge from node 'u' to node 'v'.
 - The last line contains two integers 'S' and 'D', the source and destination nodes respectively.

Output:

For each test case, output:
 - An integer 'N' representing the number of valid paths from 'S' to 'D'.
 - Each of the following 'N' lines should list the nodes in one of the paths from 'S' to 'D'.
 If there are multiple paths, they should be printed in lexicographically sorted order.

Example:

Input:
T = 1, N = 4, M = 4, S = 0, D = 3
Edges:
0 1
1 2
2 3
2 0
Output:
2
0 1 2 3
0 2 3
In this example graph, there are two paths from 0 to 3.

Constraints:

• 1 <= T <= 5
• 1 <= N <= 5
• 1 <= M <= 10
• 0 <= u, v, S, D <= N - 1

Note:

You don't need to print anything; implement the function and return the answer.