Question:
In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 4
node 0 should be visited before node 1
node 2 should be visited before node 1
node 3 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 and node 3, node 0 and node 3 can be visited first.
Since visiting node 4 requires visiting node 0 first, after node 0 is visited, node 4 can be visited.
Since visiting node 2 requires visiting node 3 first, after node 3 is visited, node 2 can be visited.
Since visiting node 1 requires visiting node 0, node 2 first, after node 0 and node 2 are visited, node 1 can be visited. So the solution is: 0,3,4,2,1.

In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 3
node 4 should be visited before node 0
node 4 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 4, node 4 can be visited first.
Since visiting node 0, node 3 requires visiting node 4 first, after node 4 is visited, node 0 and node 3 can be visited.
Since visiting node 1 requires visiting node 0, node 3, node 4 first, after node 0, node 3, and node 4 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3 first, after node 1 and node 3 are visited, node 2 can be visited. So the solution is: 4,0,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 3
node 1 should be visited before node 2
node 3 should be visited before node 2
node 4 should be visited before node 1
node 4 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 node 4 and node 5, node 0 node 4 and node 5 can be visited first.
Since visiting node 3 requires visiting node 0 first, after node 0 is visited, node 3 can be visited.
Since visiting node 1 requires visiting node 4, node 5 first, after node 4 and node 5 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3, node 4, node 5 first, after node 1, node 3, node 4, and node 5 are visited, node 2 can be visited. So the solution is: 0,4,5,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 0
node 3 should be visited before node 0
node 3 should be visited before node 5
node 4 should be visited before node 3
node 4 should be visited before node 2
node 4 should be visited before node 0
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 1 and node 4, node 1 and node 4 can be visited first.
Since visiting node 2 requires visiting node 1, node 4 first, after node 1 and node 4 are visited, node 2 can be visited.
Since visiting node 3 requires visiting node 4 first, after node 4 is visited, node 3 can be visited.
Since visiting node 0 requires visiting node 1, node 3, node 4 first, after node 1, node 3, and node 4 are visited, node 0 can be visited.
Since visiting node 5 requires visiting node 0, node 3 first, after node 0 and node 3 are visited, node 5 can be visited. So the solution is: 1,4,2,3,0,5.

In a directed graph with 7 nodes numbered from 0 to 6:
node 0 should be visited before node 6
node 2 should be visited before node 0
node 2 should be visited before node 5
node 4 should be visited before node 1
node 4 should be visited before node 3
node 6 should be visited before node 3
node 6 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 2 and node 4, node 2 and node 4 can be visited first.
Since visiting node 0 requires visiting node 2 first, after node 2 is visited, node 0 can be visited.
Since visiting node 1 requires visiting node 4 first, after node 4 is visited, node 1 can be visited.
Since visiting node 6 requires visiting node 0 first, after node 0 is visited, node 6 can be visited.
Since visiting node 5 requires visiting node 2, node 6 first, after node 2 and node 6 are visited, node 5 can be visited.
Since visiting node 3 requires visiting node 4, node 6 first, after node 4 and node 6 are visited, node 3 can be visited. So the solution is: 2,4,0,1,6,5,3.

In a directed graph with 12 nodes numbered from 0 to 11:
node 0 should be visited before node 9
node 0 should be visited before node 5
node 0 should be visited before node 4
node 0 should be visited before node 6
node 0 should be visited before node 10
node 1 should be visited before node 0
node 1 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 4
node 1 should be visited before node 6
node 1 should be visited before node 10
node 2 should be visited before node 4
node 2 should be visited before node 6
node 2 should be visited before node 11
node 2 should be visited before node 10
node 2 should be visited before node 8
node 3 should be visited before node 1
node 3 should be visited before node 7
node 3 should be visited before node 0
node 3 should be visited before node 9
node 3 should be visited before node 5
node 3 should be visited before node 2
node 3 should be visited before node 6
node 3 should be visited before node 11
node 3 should be visited before node 10
node 3 should be visited before node 8
node 4 should be visited before node 6
node 4 should be visited before node 11
node 4 should be visited before node 8
node 5 should be visited before node 2
node 5 should be visited before node 4
node 5 should be visited before node 6
node 5 should be visited before node 11
node 5 should be visited before node 10
node 5 should be visited before node 8
node 6 should be visited before node 11
node 6 should be visited before node 10
node 6 should be visited before node 8
node 7 should be visited before node 0
node 7 should be visited before node 9
node 7 should be visited before node 5
node 7 should be visited before node 2
node 7 should be visited before node 4
node 7 should be visited before node 6
node 7 should be visited before node 11
node 7 should be visited before node 10
node 7 should be visited before node 8
node 9 should be visited before node 2
node 9 should be visited before node 4
node 9 should be visited before node 6
node 9 should be visited before node 11
node 9 should be visited before node 8
node 10 should be visited before node 8
node 11 should be visited before node 8
Q: Can all the nodes be visited? Give the solution.
A:

Answer: The solution is: 3,1,7,0,9,5,2,4,6,11,10,8.


Question:
In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 4
node 0 should be visited before node 1
node 2 should be visited before node 1
node 3 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 and node 3, node 0 and node 3 can be visited first.
Since visiting node 4 requires visiting node 0 first, after node 0 is visited, node 4 can be visited.
Since visiting node 2 requires visiting node 3 first, after node 3 is visited, node 2 can be visited.
Since visiting node 1 requires visiting node 0, node 2 first, after node 0 and node 2 are visited, node 1 can be visited. So the solution is: 0,3,4,2,1.

In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 3
node 4 should be visited before node 0
node 4 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 4, node 4 can be visited first.
Since visiting node 0, node 3 requires visiting node 4 first, after node 4 is visited, node 0 and node 3 can be visited.
Since visiting node 1 requires visiting node 0, node 3, node 4 first, after node 0, node 3, and node 4 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3 first, after node 1 and node 3 are visited, node 2 can be visited. So the solution is: 4,0,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 3
node 1 should be visited before node 2
node 3 should be visited before node 2
node 4 should be visited before node 1
node 4 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 node 4 and node 5, node 0 node 4 and node 5 can be visited first.
Since visiting node 3 requires visiting node 0 first, after node 0 is visited, node 3 can be visited.
Since visiting node 1 requires visiting node 4, node 5 first, after node 4 and node 5 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3, node 4, node 5 first, after node 1, node 3, node 4, and node 5 are visited, node 2 can be visited. So the solution is: 0,4,5,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 0
node 3 should be visited before node 0
node 3 should be visited before node 5
node 4 should be visited before node 3
node 4 should be visited before node 2
node 4 should be visited before node 0
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 1 and node 4, node 1 and node 4 can be visited first.
Since visiting node 2 requires visiting node 1, node 4 first, after node 1 and node 4 are visited, node 2 can be visited.
Since visiting node 3 requires visiting node 4 first, after node 4 is visited, node 3 can be visited.
Since visiting node 0 requires visiting node 1, node 3, node 4 first, after node 1, node 3, and node 4 are visited, node 0 can be visited.
Since visiting node 5 requires visiting node 0, node 3 first, after node 0 and node 3 are visited, node 5 can be visited. So the solution is: 1,4,2,3,0,5.

In a directed graph with 7 nodes numbered from 0 to 6:
node 0 should be visited before node 6
node 2 should be visited before node 0
node 2 should be visited before node 5
node 4 should be visited before node 1
node 4 should be visited before node 3
node 6 should be visited before node 3
node 6 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 2 and node 4, node 2 and node 4 can be visited first.
Since visiting node 0 requires visiting node 2 first, after node 2 is visited, node 0 can be visited.
Since visiting node 1 requires visiting node 4 first, after node 4 is visited, node 1 can be visited.
Since visiting node 6 requires visiting node 0 first, after node 0 is visited, node 6 can be visited.
Since visiting node 5 requires visiting node 2, node 6 first, after node 2 and node 6 are visited, node 5 can be visited.
Since visiting node 3 requires visiting node 4, node 6 first, after node 4 and node 6 are visited, node 3 can be visited. So the solution is: 2,4,0,1,6,5,3.

In a directed graph with 9 nodes numbered from 0 to 8:
node 0 should be visited before node 2
node 0 should be visited before node 6
node 0 should be visited before node 3
node 1 should be visited before node 3
node 4 should be visited before node 8
node 4 should be visited before node 5
node 6 should be visited before node 8
node 6 should be visited before node 5
node 7 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A:

Answer: The solution is: 0,1,4,7,2,6,3,8,5.


Question:
In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 4
node 0 should be visited before node 1
node 2 should be visited before node 1
node 3 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 and node 3, node 0 and node 3 can be visited first.
Since visiting node 4 requires visiting node 0 first, after node 0 is visited, node 4 can be visited.
Since visiting node 2 requires visiting node 3 first, after node 3 is visited, node 2 can be visited.
Since visiting node 1 requires visiting node 0, node 2 first, after node 0 and node 2 are visited, node 1 can be visited. So the solution is: 0,3,4,2,1.

In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 3
node 4 should be visited before node 0
node 4 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 4, node 4 can be visited first.
Since visiting node 0, node 3 requires visiting node 4 first, after node 4 is visited, node 0 and node 3 can be visited.
Since visiting node 1 requires visiting node 0, node 3, node 4 first, after node 0, node 3, and node 4 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3 first, after node 1 and node 3 are visited, node 2 can be visited. So the solution is: 4,0,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 3
node 1 should be visited before node 2
node 3 should be visited before node 2
node 4 should be visited before node 1
node 4 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 node 4 and node 5, node 0 node 4 and node 5 can be visited first.
Since visiting node 3 requires visiting node 0 first, after node 0 is visited, node 3 can be visited.
Since visiting node 1 requires visiting node 4, node 5 first, after node 4 and node 5 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3, node 4, node 5 first, after node 1, node 3, node 4, and node 5 are visited, node 2 can be visited. So the solution is: 0,4,5,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 0
node 3 should be visited before node 0
node 3 should be visited before node 5
node 4 should be visited before node 3
node 4 should be visited before node 2
node 4 should be visited before node 0
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 1 and node 4, node 1 and node 4 can be visited first.
Since visiting node 2 requires visiting node 1, node 4 first, after node 1 and node 4 are visited, node 2 can be visited.
Since visiting node 3 requires visiting node 4 first, after node 4 is visited, node 3 can be visited.
Since visiting node 0 requires visiting node 1, node 3, node 4 first, after node 1, node 3, and node 4 are visited, node 0 can be visited.
Since visiting node 5 requires visiting node 0, node 3 first, after node 0 and node 3 are visited, node 5 can be visited. So the solution is: 1,4,2,3,0,5.

In a directed graph with 7 nodes numbered from 0 to 6:
node 0 should be visited before node 6
node 2 should be visited before node 0
node 2 should be visited before node 5
node 4 should be visited before node 1
node 4 should be visited before node 3
node 6 should be visited before node 3
node 6 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 2 and node 4, node 2 and node 4 can be visited first.
Since visiting node 0 requires visiting node 2 first, after node 2 is visited, node 0 can be visited.
Since visiting node 1 requires visiting node 4 first, after node 4 is visited, node 1 can be visited.
Since visiting node 6 requires visiting node 0 first, after node 0 is visited, node 6 can be visited.
Since visiting node 5 requires visiting node 2, node 6 first, after node 2 and node 6 are visited, node 5 can be visited.
Since visiting node 3 requires visiting node 4, node 6 first, after node 4 and node 6 are visited, node 3 can be visited. So the solution is: 2,4,0,1,6,5,3.

In a directed graph with 8 nodes numbered from 0 to 7:
node 0 should be visited before node 4
node 1 should be visited before node 4
node 2 should be visited before node 1
node 2 should be visited before node 6
node 2 should be visited before node 7
node 3 should be visited before node 1
node 3 should be visited before node 4
node 3 should be visited before node 5
node 4 should be visited before node 5
node 4 should be visited before node 7
node 5 should be visited before node 7
node 6 should be visited before node 0
node 6 should be visited before node 7
Q: Can all the nodes be visited? Give the solution.
A:

Answer: The solution is: 2,3,6,1,0,4,5,7.


Question:
In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 4
node 0 should be visited before node 1
node 2 should be visited before node 1
node 3 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 and node 3, node 0 and node 3 can be visited first.
Since visiting node 4 requires visiting node 0 first, after node 0 is visited, node 4 can be visited.
Since visiting node 2 requires visiting node 3 first, after node 3 is visited, node 2 can be visited.
Since visiting node 1 requires visiting node 0, node 2 first, after node 0 and node 2 are visited, node 1 can be visited. So the solution is: 0,3,4,2,1.

In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 3
node 4 should be visited before node 0
node 4 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 4, node 4 can be visited first.
Since visiting node 0, node 3 requires visiting node 4 first, after node 4 is visited, node 0 and node 3 can be visited.
Since visiting node 1 requires visiting node 0, node 3, node 4 first, after node 0, node 3, and node 4 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3 first, after node 1 and node 3 are visited, node 2 can be visited. So the solution is: 4,0,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 3
node 1 should be visited before node 2
node 3 should be visited before node 2
node 4 should be visited before node 1
node 4 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 node 4 and node 5, node 0 node 4 and node 5 can be visited first.
Since visiting node 3 requires visiting node 0 first, after node 0 is visited, node 3 can be visited.
Since visiting node 1 requires visiting node 4, node 5 first, after node 4 and node 5 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3, node 4, node 5 first, after node 1, node 3, node 4, and node 5 are visited, node 2 can be visited. So the solution is: 0,4,5,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 0
node 3 should be visited before node 0
node 3 should be visited before node 5
node 4 should be visited before node 3
node 4 should be visited before node 2
node 4 should be visited before node 0
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 1 and node 4, node 1 and node 4 can be visited first.
Since visiting node 2 requires visiting node 1, node 4 first, after node 1 and node 4 are visited, node 2 can be visited.
Since visiting node 3 requires visiting node 4 first, after node 4 is visited, node 3 can be visited.
Since visiting node 0 requires visiting node 1, node 3, node 4 first, after node 1, node 3, and node 4 are visited, node 0 can be visited.
Since visiting node 5 requires visiting node 0, node 3 first, after node 0 and node 3 are visited, node 5 can be visited. So the solution is: 1,4,2,3,0,5.

In a directed graph with 7 nodes numbered from 0 to 6:
node 0 should be visited before node 6
node 2 should be visited before node 0
node 2 should be visited before node 5
node 4 should be visited before node 1
node 4 should be visited before node 3
node 6 should be visited before node 3
node 6 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 2 and node 4, node 2 and node 4 can be visited first.
Since visiting node 0 requires visiting node 2 first, after node 2 is visited, node 0 can be visited.
Since visiting node 1 requires visiting node 4 first, after node 4 is visited, node 1 can be visited.
Since visiting node 6 requires visiting node 0 first, after node 0 is visited, node 6 can be visited.
Since visiting node 5 requires visiting node 2, node 6 first, after node 2 and node 6 are visited, node 5 can be visited.
Since visiting node 3 requires visiting node 4, node 6 first, after node 4 and node 6 are visited, node 3 can be visited. So the solution is: 2,4,0,1,6,5,3.

In a directed graph with 7 nodes numbered from 0 to 6:
node 1 should be visited before node 6
node 1 should be visited before node 4
node 3 should be visited before node 1
node 5 should be visited before node 4
node 5 should be visited before node 2
node 6 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A:

Answer: The solution is: 0,3,5,1,6,4,2.


Question:
In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 4
node 0 should be visited before node 1
node 2 should be visited before node 1
node 3 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 and node 3, node 0 and node 3 can be visited first.
Since visiting node 4 requires visiting node 0 first, after node 0 is visited, node 4 can be visited.
Since visiting node 2 requires visiting node 3 first, after node 3 is visited, node 2 can be visited.
Since visiting node 1 requires visiting node 0, node 2 first, after node 0 and node 2 are visited, node 1 can be visited. So the solution is: 0,3,4,2,1.

In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 3
node 4 should be visited before node 0
node 4 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 4, node 4 can be visited first.
Since visiting node 0, node 3 requires visiting node 4 first, after node 4 is visited, node 0 and node 3 can be visited.
Since visiting node 1 requires visiting node 0, node 3, node 4 first, after node 0, node 3, and node 4 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3 first, after node 1 and node 3 are visited, node 2 can be visited. So the solution is: 4,0,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 3
node 1 should be visited before node 2
node 3 should be visited before node 2
node 4 should be visited before node 1
node 4 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 node 4 and node 5, node 0 node 4 and node 5 can be visited first.
Since visiting node 3 requires visiting node 0 first, after node 0 is visited, node 3 can be visited.
Since visiting node 1 requires visiting node 4, node 5 first, after node 4 and node 5 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3, node 4, node 5 first, after node 1, node 3, node 4, and node 5 are visited, node 2 can be visited. So the solution is: 0,4,5,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 0
node 3 should be visited before node 0
node 3 should be visited before node 5
node 4 should be visited before node 3
node 4 should be visited before node 2
node 4 should be visited before node 0
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 1 and node 4, node 1 and node 4 can be visited first.
Since visiting node 2 requires visiting node 1, node 4 first, after node 1 and node 4 are visited, node 2 can be visited.
Since visiting node 3 requires visiting node 4 first, after node 4 is visited, node 3 can be visited.
Since visiting node 0 requires visiting node 1, node 3, node 4 first, after node 1, node 3, and node 4 are visited, node 0 can be visited.
Since visiting node 5 requires visiting node 0, node 3 first, after node 0 and node 3 are visited, node 5 can be visited. So the solution is: 1,4,2,3,0,5.

In a directed graph with 7 nodes numbered from 0 to 6:
node 0 should be visited before node 6
node 2 should be visited before node 0
node 2 should be visited before node 5
node 4 should be visited before node 1
node 4 should be visited before node 3
node 6 should be visited before node 3
node 6 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 2 and node 4, node 2 and node 4 can be visited first.
Since visiting node 0 requires visiting node 2 first, after node 2 is visited, node 0 can be visited.
Since visiting node 1 requires visiting node 4 first, after node 4 is visited, node 1 can be visited.
Since visiting node 6 requires visiting node 0 first, after node 0 is visited, node 6 can be visited.
Since visiting node 5 requires visiting node 2, node 6 first, after node 2 and node 6 are visited, node 5 can be visited.
Since visiting node 3 requires visiting node 4, node 6 first, after node 4 and node 6 are visited, node 3 can be visited. So the solution is: 2,4,0,1,6,5,3.

In a directed graph with 11 nodes numbered from 0 to 10:
node 0 should be visited before node 2
node 0 should be visited before node 6
node 0 should be visited before node 10
node 0 should be visited before node 5
node 0 should be visited before node 8
node 1 should be visited before node 9
node 1 should be visited before node 0
node 1 should be visited before node 7
node 1 should be visited before node 10
node 1 should be visited before node 8
node 2 should be visited before node 6
node 2 should be visited before node 5
node 3 should be visited before node 1
node 3 should be visited before node 4
node 3 should be visited before node 7
node 3 should be visited before node 2
node 3 should be visited before node 5
node 4 should be visited before node 0
node 4 should be visited before node 2
node 4 should be visited before node 6
node 4 should be visited before node 5
node 5 should be visited before node 8
node 6 should be visited before node 10
node 6 should be visited before node 5
node 6 should be visited before node 8
node 7 should be visited before node 2
node 7 should be visited before node 6
node 7 should be visited before node 5
node 9 should be visited before node 4
node 9 should be visited before node 7
node 9 should be visited before node 6
node 10 should be visited before node 8
Q: Can all the nodes be visited? Give the solution.
A:

Answer: The solution is: 3,1,9,4,7,0,2,6,10,5,8.


Question:
In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 4
node 0 should be visited before node 1
node 2 should be visited before node 1
node 3 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 and node 3, node 0 and node 3 can be visited first.
Since visiting node 4 requires visiting node 0 first, after node 0 is visited, node 4 can be visited.
Since visiting node 2 requires visiting node 3 first, after node 3 is visited, node 2 can be visited.
Since visiting node 1 requires visiting node 0, node 2 first, after node 0 and node 2 are visited, node 1 can be visited. So the solution is: 0,3,4,2,1.

In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 3
node 4 should be visited before node 0
node 4 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 4, node 4 can be visited first.
Since visiting node 0, node 3 requires visiting node 4 first, after node 4 is visited, node 0 and node 3 can be visited.
Since visiting node 1 requires visiting node 0, node 3, node 4 first, after node 0, node 3, and node 4 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3 first, after node 1 and node 3 are visited, node 2 can be visited. So the solution is: 4,0,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 3
node 1 should be visited before node 2
node 3 should be visited before node 2
node 4 should be visited before node 1
node 4 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 node 4 and node 5, node 0 node 4 and node 5 can be visited first.
Since visiting node 3 requires visiting node 0 first, after node 0 is visited, node 3 can be visited.
Since visiting node 1 requires visiting node 4, node 5 first, after node 4 and node 5 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3, node 4, node 5 first, after node 1, node 3, node 4, and node 5 are visited, node 2 can be visited. So the solution is: 0,4,5,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 0
node 3 should be visited before node 0
node 3 should be visited before node 5
node 4 should be visited before node 3
node 4 should be visited before node 2
node 4 should be visited before node 0
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 1 and node 4, node 1 and node 4 can be visited first.
Since visiting node 2 requires visiting node 1, node 4 first, after node 1 and node 4 are visited, node 2 can be visited.
Since visiting node 3 requires visiting node 4 first, after node 4 is visited, node 3 can be visited.
Since visiting node 0 requires visiting node 1, node 3, node 4 first, after node 1, node 3, and node 4 are visited, node 0 can be visited.
Since visiting node 5 requires visiting node 0, node 3 first, after node 0 and node 3 are visited, node 5 can be visited. So the solution is: 1,4,2,3,0,5.

In a directed graph with 7 nodes numbered from 0 to 6:
node 0 should be visited before node 6
node 2 should be visited before node 0
node 2 should be visited before node 5
node 4 should be visited before node 1
node 4 should be visited before node 3
node 6 should be visited before node 3
node 6 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 2 and node 4, node 2 and node 4 can be visited first.
Since visiting node 0 requires visiting node 2 first, after node 2 is visited, node 0 can be visited.
Since visiting node 1 requires visiting node 4 first, after node 4 is visited, node 1 can be visited.
Since visiting node 6 requires visiting node 0 first, after node 0 is visited, node 6 can be visited.
Since visiting node 5 requires visiting node 2, node 6 first, after node 2 and node 6 are visited, node 5 can be visited.
Since visiting node 3 requires visiting node 4, node 6 first, after node 4 and node 6 are visited, node 3 can be visited. So the solution is: 2,4,0,1,6,5,3.

In a directed graph with 13 nodes numbered from 0 to 12:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 5
node 3 should be visited before node 9
node 3 should be visited before node 0
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 7
node 4 should be visited before node 2
node 5 should be visited before node 11
node 5 should be visited before node 9
node 5 should be visited before node 8
node 5 should be visited before node 6
node 5 should be visited before node 7
node 5 should be visited before node 2
node 6 should be visited before node 1
node 8 should be visited before node 2
node 9 should be visited before node 6
node 9 should be visited before node 7
node 9 should be visited before node 2
node 10 should be visited before node 12
node 10 should be visited before node 3
node 10 should be visited before node 11
node 10 should be visited before node 0
node 10 should be visited before node 6
node 10 should be visited before node 1
node 10 should be visited before node 7
node 11 should be visited before node 9
node 11 should be visited before node 0
node 11 should be visited before node 6
node 11 should be visited before node 1
node 11 should be visited before node 7
node 11 should be visited before node 2
node 12 should be visited before node 4
node 12 should be visited before node 5
node 12 should be visited before node 9
node 12 should be visited before node 0
node 12 should be visited before node 6
node 12 should be visited before node 1
node 12 should be visited before node 7
node 12 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A:

Answer: The solution is: 10,12,3,4,5,11,8,9,0,6,7,1,2.


Question:
In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 4
node 0 should be visited before node 1
node 2 should be visited before node 1
node 3 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 and node 3, node 0 and node 3 can be visited first.
Since visiting node 4 requires visiting node 0 first, after node 0 is visited, node 4 can be visited.
Since visiting node 2 requires visiting node 3 first, after node 3 is visited, node 2 can be visited.
Since visiting node 1 requires visiting node 0, node 2 first, after node 0 and node 2 are visited, node 1 can be visited. So the solution is: 0,3,4,2,1.

In a directed graph with 5 nodes numbered from 0 to 4:
node 0 should be visited before node 1
node 1 should be visited before node 2
node 3 should be visited before node 1
node 3 should be visited before node 2
node 4 should be visited before node 3
node 4 should be visited before node 0
node 4 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 4, node 4 can be visited first.
Since visiting node 0, node 3 requires visiting node 4 first, after node 4 is visited, node 0 and node 3 can be visited.
Since visiting node 1 requires visiting node 0, node 3, node 4 first, after node 0, node 3, and node 4 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3 first, after node 1 and node 3 are visited, node 2 can be visited. So the solution is: 4,0,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 3
node 1 should be visited before node 2
node 3 should be visited before node 2
node 4 should be visited before node 1
node 4 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 2
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 0 node 4 and node 5, node 0 node 4 and node 5 can be visited first.
Since visiting node 3 requires visiting node 0 first, after node 0 is visited, node 3 can be visited.
Since visiting node 1 requires visiting node 4, node 5 first, after node 4 and node 5 are visited, node 1 can be visited.
Since visiting node 2 requires visiting node 1, node 3, node 4, node 5 first, after node 1, node 3, node 4, and node 5 are visited, node 2 can be visited. So the solution is: 0,4,5,3,1,2.

In a directed graph with 6 nodes numbered from 0 to 5:
node 0 should be visited before node 5
node 1 should be visited before node 2
node 1 should be visited before node 0
node 3 should be visited before node 0
node 3 should be visited before node 5
node 4 should be visited before node 3
node 4 should be visited before node 2
node 4 should be visited before node 0
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 1 and node 4, node 1 and node 4 can be visited first.
Since visiting node 2 requires visiting node 1, node 4 first, after node 1 and node 4 are visited, node 2 can be visited.
Since visiting node 3 requires visiting node 4 first, after node 4 is visited, node 3 can be visited.
Since visiting node 0 requires visiting node 1, node 3, node 4 first, after node 1, node 3, and node 4 are visited, node 0 can be visited.
Since visiting node 5 requires visiting node 0, node 3 first, after node 0 and node 3 are visited, node 5 can be visited. So the solution is: 1,4,2,3,0,5.

In a directed graph with 7 nodes numbered from 0 to 6:
node 0 should be visited before node 6
node 2 should be visited before node 0
node 2 should be visited before node 5
node 4 should be visited before node 1
node 4 should be visited before node 3
node 6 should be visited before node 3
node 6 should be visited before node 5
Q: Can all the nodes be visited? Give the solution.
A: Since no nodes are required to be visited before node 2 and node 4, node 2 and node 4 can be visited first.
Since visiting node 0 requires visiting node 2 first, after node 2 is visited, node 0 can be visited.
Since visiting node 1 requires visiting node 4 first, after node 4 is visited, node 1 can be visited.
Since visiting node 6 requires visiting node 0 first, after node 0 is visited, node 6 can be visited.
Since visiting node 5 requires visiting node 2, node 6 first, after node 2 and node 6 are visited, node 5 can be visited.
Since visiting node 3 requires visiting node 4, node 6 first, after node 4 and node 6 are visited, node 3 can be visited. So the solution is: 2,4,0,1,6,5,3.

In a directed graph with 28 nodes numbered from 0 to 27:
node 0 should be visited before node 4
node 0 should be visited before node 21
node 0 should be visited before node 3
node 0 should be visited before node 6
node 0 should be visited before node 19
node 1 should be visited before node 26
node 2 should be visited before node 1
node 3 should be visited before node 5
node 3 should be visited before node 8
node 4 should be visited before node 3
node 4 should be visited before node 9
node 4 should be visited before node 22
node 4 should be visited before node 19
node 5 should be visited before node 22
node 5 should be visited before node 17
node 5 should be visited before node 2
node 5 should be visited before node 1
node 5 should be visited before node 8
node 5 should be visited before node 26
node 6 should be visited before node 24
node 6 should be visited before node 19
node 6 should be visited before node 8
node 7 should be visited before node 27
node 7 should be visited before node 0
node 7 should be visited before node 4
node 7 should be visited before node 18
node 7 should be visited before node 3
node 7 should be visited before node 9
node 7 should be visited before node 5
node 7 should be visited before node 22
node 7 should be visited before node 24
node 7 should be visited before node 8
node 9 should be visited before node 24
node 9 should be visited before node 8
node 10 should be visited before node 12
node 10 should be visited before node 9
node 10 should be visited before node 6
node 10 should be visited before node 2
node 10 should be visited before node 26
node 11 should be visited before node 6
node 11 should be visited before node 24
node 11 should be visited before node 17
node 11 should be visited before node 26
node 12 should be visited before node 14
node 12 should be visited before node 11
node 12 should be visited before node 5
node 12 should be visited before node 2
node 13 should be visited before node 18
node 13 should be visited before node 14
node 13 should be visited before node 5
node 13 should be visited before node 19
node 13 should be visited before node 1
node 14 should be visited before node 22
node 14 should be visited before node 24
node 14 should be visited before node 19
node 14 should be visited before node 17
node 14 should be visited before node 1
node 15 should be visited before node 13
node 15 should be visited before node 18
node 15 should be visited before node 12
node 15 should be visited before node 19
node 15 should be visited before node 1
node 17 should be visited before node 2
node 17 should be visited before node 1
node 18 should be visited before node 12
node 18 should be visited before node 3
node 18 should be visited before node 11
node 18 should be visited before node 19
node 18 should be visited before node 1
node 20 should be visited before node 15
node 20 should be visited before node 10
node 20 should be visited before node 12
node 20 should be visited before node 16
node 20 should be visited before node 22
node 20 should be visited before node 17
node 20 should be visited before node 2
node 21 should be visited before node 3
node 21 should be visited before node 16
node 21 should be visited before node 1
node 21 should be visited before node 8
node 22 should be visited before node 8
node 23 should be visited before node 18
node 23 should be visited before node 21
node 23 should be visited before node 17
node 23 should be visited before node 8
node 24 should be visited before node 17
node 24 should be visited before node 8
node 25 should be visited before node 13
node 25 should be visited before node 12
node 25 should be visited before node 14
node 25 should be visited before node 16
node 25 should be visited before node 5
node 25 should be visited before node 22
node 25 should be visited before node 6
node 25 should be visited before node 2
node 25 should be visited before node 1
node 27 should be visited before node 15
node 27 should be visited before node 0
node 27 should be visited before node 14
node 27 should be visited before node 22
node 27 should be visited before node 1
Q: Can all the nodes be visited? Give the solution.
A:

Answer: The solution is: 7,20,23,25,27,10,15,0,13,4,21,18,9,16,12,3,14,11,5,6,22,24,19,17,8,2,1,26.