if vertex.isMarked():
count += 1
print("Expect 4: " + str(count))
g.clearVertexMarks()
count = 0
for vertex in g.vertices():
if vertex.isMarked():
count += 1
print("Expect 0: " + str(count))
# Insert some edges
g.addEdge("a", "b", 1)
g.addEdge("c", "d", 2)
# Mark edges, count marks, clear marks, count marks
for edge in g.edges():
edge.setMark();
count = 0;
for edge in g.edges():
if edge.isMarked():
count += 1
print("Expect 2: " + str(count))
g.clearEdgeMarks()
count = 0;
for edge in g.edges():
if edge.isMarked():
count += 1
print("Expect 0: " + str(count))
# Clear graph
g.clear()
def topologicalSort(graph):
# <your code>
graph = LinkedDirectedGraph()
# The graph represents the following course prerequisites:
# A requires nothing
# B requires nothing
# C requires A
# D requires A, B, and C
# E requires C
# F requires B and D
# G requires E and F
# H requires C, F, and G
# Part 2:
# Add the vertices:
# <your code>
graph.addVertex("A")
graph.addVertex("B")
graph.addVertex("C")
graph.addVertex("D")
graph.addVertex("E")
graph.addVertex("F")
graph.addVertex("G")
graph.addVertex("H")
# Part 3:
# Add the edges:
# <your code>
graph.addEdge("A", "C", 0)
graph.addEdge("A", "D", 0)
graph.addEdge("B", "D", 0)
graph.addEdge("C", "D", 0)
graph.addEdge("C", "E", 0)
graph.addEdge("B", "F", 0)
graph.addEdge("D", "F", 0)
graph.addEdge("E", "G", 0)
graph.addEdge("F", "G", 0)
graph.addEdge("C", "H", 0)
graph.addEdge("F", "H", 0)
graph.addEdge("G", "H", 0)
print("Graph:")
print(graph)
print("Courses:")
# Part 4:
# Display each vertex on a separate line:
# <your code>
for vertex in graph.vertices():
print(str(vertex))
print()
print("Prerequisites:")
# Part 5:
# Display each edge on a separate line:
# <your code>
for edge in graph.edges():
print(str(edge))
print("One possible order to take the courses:")
# Part 6:
# Display the courses in prerequisite (topological) order:
# <your code>
stack = []
for i in graph.vertices():
if not i.isMarked():
topologicalSortStack(i, stack)
print(" ".join(str(x) for x in stack))
print()
