mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-28 07:21:07 +00:00
47 lines
979 B
Python
47 lines
979 B
Python
|
from __future__ import print_function
|
||
|
|
# n - no of nodes, m - no of edges
|
||
|
|
n, m = list(map(int,raw_input().split()))
|
||
|
|
|
||
|
|
g = [[] for i in range(n)] #graph
|
||
|
|
r = [[] for i in range(n)] #reversed graph
|
||
|
|
# input graph data (edges)
|
||
|
|
for i in range(m):
|
||
|
|
u, v = list(map(int,raw_input().split()))
|
||
|
|
g[u].append(v)
|
||
|
|
r[v].append(u)
|
||
|
|
|
||
|
|
stack = []
|
||
|
|
visit = [False]*n
|
||
|
|
scc = []
|
||
|
|
component = []
|
||
|
|
|
||
|
|
def dfs(u):
|
||
|
|
global g, r, scc, component, visit, stack
|
||
|
|
if visit[u]: return
|
||
|
|
visit[u] = True
|
||
|
|
for v in g[u]:
|
||
|
|
dfs(v)
|
||
|
|
stack.append(u)
|
||
|
|
|
||
|
|
def dfs2(u):
|
||
|
|
global g, r, scc, component, visit, stack
|
||
|
|
if visit[u]: return
|
||
|
|
visit[u] = True
|
||
|
|
component.append(u)
|
||
|
|
for v in r[u]:
|
||
|
|
dfs2(v)
|
||
|
|
|
||
|
|
def kosaraju():
|
||
|
|
global g, r, scc, component, visit, stack
|
||
|
|
for i in range(n):
|
||
|
|
dfs(i)
|
||
|
|
visit = [False]*n
|
||
|
|
for i in stack[::-1]:
|
||
|
|
if visit[i]: continue
|
||
|
|
component = []
|
||
|
|
dfs2(i)
|
||
|
|
scc.append(component)
|
||
|
|
return scc
|
||
|
|
|
||
|
|
print(kosaraju())
|