def __init__(self, g: DiGraph):
self.id = [None]*(g.V+1)
self.marked = [False]*(g.V+1)
self.curr_component = 0
self.num_of_components = 0
tsort = TopologicalSort(g.reverse())
postorder = tsort.getPostorder()
self.g = g
for elem in postorder:
if not self.marked[elem]:
self.dfs(g, elem)
self.curr_component += 1
self.num_of_components += 1
def dfs(self, g: DiGraph, i: int):
self.onStack[i] = True
self.marked[i] = True
for node in g.close(i):
if self.hasCycle:
# short circuit if cycle
return
elif not self.marked[i]:
self.edgeTo[node] = i
self.dfs(g, node)
elif self.onStack[node]:
# There is a cycle
cycle = []
init = i
while init != node:
cycle.append(init)
init = self.edgeTo[init]
cycle.append(node)
return cycle
self.onStack[i] = False
def dfs(self, g: DiGraph, v: int):
self.marked[v] = True
self.id[v] = self.curr_component
for node in g.close(v):
if not self.marked[node]:
self.dfs(g, node)
def dfs(self, g: DiGraph, i: int):
self.marked[i] = True
for nodes in g.close(i):
if not self.marked[nodes]:
self.dfs(g, nodes)
self.stack.append(i)