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89 lines
1.7 KiB
Python
89 lines
1.7 KiB
Python
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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"""
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@source: http://codehiker.wordpress.com/2012/04/06/kosarajus-scc/
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I made minor changs
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"""
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import sys
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sys.setrecursionlimit(300000)
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source = 'SCC.txt'
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N = 875714
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#globals
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visited = {}
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finish = {}
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leader = {}
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def getG(source):
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""" Read the Graph from a textfile """
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G = {}
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Grev = {}
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for i in range(1,N+1):
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G[i] = []
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Grev[i] = []
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fin = open(source)
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for line in fin:
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v1 = int(line.split()[0])
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v2 = int(line.split()[1])
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G[v1].append(v2)
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Grev[v2].append(v1)
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fin.close()
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return G, Grev
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def init():
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for i in range(1,N+1):
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visited[i] = 0
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finish[i] = 0
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leader[i] = 0
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def dfs(G, i):
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global t
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visited[i] = 1
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leader[i] = s
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for j in G[i]:
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if(visited[j]==0): dfs(G,j)
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t = t + 1
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finish[i] = t
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def dfs_loop(G):
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global t
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global s
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t = 0 #number of nodes processed so far
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s = 0 #current source vertex
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i = N
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while(i>0):
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if(visited[i]==0):
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s=i
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dfs(G,i)
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i=i-1
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if __name__ == "__main__":
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init()
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g, grev=getG()
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dfs_loop(grev) #THE FIRST LOOP ON REVERSE GRAPH
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# construct new graph
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newGraph = {}
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for i in range(1, N+1):
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temp = []
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for x in g[i]: temp.append(finish[x])
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newGraph[finish[i]] = temp
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init()
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dfs_loop(newGraph) #THE SECOND LOOP
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# statistics
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lst = sorted(leader.values())
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stat = []
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pre = 0
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for i in range(0,N-1):
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if lst[i] != lst[i+1]:
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stat.append(i + 1 - pre)
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pre=i+1
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stat.append(N-pre)
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L = sorted(stat)
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L.reverse()
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print(L[0:5])
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