{"id":63,"date":"2012-08-27T16:08:00","date_gmt":"2012-08-27T08:08:00","guid":{"rendered":"http:\/\/nike0good.jp1.rpvhost.net\/63"},"modified":"2012-08-27T16:08:00","modified_gmt":"2012-08-27T08:08:00","slug":"poj_2186_strongly_connected_components_of_a_directed_graph","status":"publish","type":"post","link":"https:\/\/nike0good.com\/?p=63","title":{"rendered":"POJ 2186\uff08\u6709\u5411\u56fe\u7684\u5f3a\u8fde\u901a\u5206\u91cf\uff09"},"content":{"rendered":"<p>\u9898\u76ee\u5927\u610f\uff1a\u7ed9\u6709\u5411\u56feG\uff0c\u6c42\u56feG\u4e2d\u6709\u591a\u5c11\u70b9\u80fd\u4ece\u6240\u6709\u8d77\u70b9\u5230\u8fbe<\/p>\n<p>\u66b4\u641c\u5fc5T\uff0c\u6545\u672c\u9898\u9700\u8981\u7528Tarjen\u6c42\u6709\u5411\u56fe\u7684\u5f3a\u8fde\u901a\u5206\u91cf\u3002<\/p>\n<p>\u7f29\u70b9\u540e\u5f97DAG\uff08\u82e5\u6709\u73af\u5219\u5c5e\u540c\u4e00\u5f3a\u8fde\u901a\u5206\u91cf\uff09<\/p>\n<p>\u7531\u4e8e\u65e0\u73af\uff0c\u6545\u8fd9\u56fe\u4e3a\u6811\u6216\u6811\u7684\u68ee\u6797<\/p>\n<p>\u5148\u5224\u65ad\u56fe\u662f\u5426\u8fde\u901a\uff0c\u82e5\u4e3a\u68ee\u6797\u5219\u65e0\u89e3<\/p>\n<p>\u5426\u5219\uff0c\u5224\u5b9a\u6bcf\u4e2aSSC\u662f\u5426\u6709\u8fde\u51fa\u7684\u8fb9\uff08\u7531\u4e8e\u56fe\u65e0\u73af,\u6545\u8fde\u51fa\u7684\u8fb9\u4e0a\u7684\u70b9\u65e0\u6cd5\u56de\u53bb\uff09<\/p>\n<p>\u7b54\u6848\u5373\u4e3a\u51fa\u5ea6\u4e3a0\u7684\u8fde\u901a\u5206\u91cf\u4e0a\u7684\u70b9<\/p>\n<p>\u5982\u679c\u4e0d\u6b62\u4e00\u4e2a\u8fd9\u6837\u7684\u70b9\uff0c\u5219\u4e0d\u540c\u7684\u70b9\u65e0\u6cd5\u4e92\u76f8\u5230\u8fbe<\/p>\n<p>\n<\/p>\n<p><pre name=\"code\" class=\"delphi\">Program P2186;\nconst\n   maxn=10000;\n   maxm=50000;\nvar\n   head,edge,tail:array[1..maxm] of longint;\n   sizeedge:longint;\n\n\n   n,m,i,j,x,y:longint;\n   ssc,c,dfs,low,outdegree,stack:array[1..maxn] of longint;\n   time,size:longint;\n   totssc:longint;\n\nprocedure addedge(u,v:longint);\nbegin\n   inc(sizeedge);\n   edge[sizeedge]:=v;\n   tail[sizeedge]:=head[u];\n   head[u]:=sizeedge;\n\nend;\n\n\nfunction min(a,b:longint):longint;\nbegin\n   if a&lt;b then exit(a) else exit(b);\nend;\nprocedure tarjen(k,father:longint);\nvar\n   i,j,p:longint;\nbegin\n   inc(time);\n   dfs[k]:=time;low[k]:=time;\n   c[k]:=1;\n   inc(size);stack[size]:=k;\n\n   p:=head[k];\n   while (p&lt;&gt;0) do\n   begin\n      i:=edge[p];\n\n      if (dfs[k]&gt;dfs[i]) then\n      begin\n         if c[i]=0 then\n         begin\n            tarjen(i,k);\n            low[k]:=min(low[k],low[i]);\n         end\n         else if c[i]=1 then low[k]:=min(low[k],dfs[i]);\n      end;\n      p:=tail[p];\n\n   end;\n   if low[k]=dfs[k] then\n   begin\n      inc(totssc);\n      repeat\n         i:=stack[size];\n         dec(size);\n         c[i]:=2;\n         ssc[i]:=totssc;\n      until ((size=0) or (i=k));\n\n   end;\nend;\nfunction main:longint;\nvar\n   i,j,tot,node,p:longint;\nbegin\n   fillchar(dfs,sizeof(dfs),0);\n   fillchar(low,sizeof(low),0);\n   fillchar(c,sizeof(c),0);\n   fillchar(outdegree,sizeof(outdegree),0);\n   time:=0;\n   totssc:=0;\n   for i:=1 to n do\n      if (dfs[i]=0) then\n      begin\n         fillchar(stack,sizeof(stack),0);\n         size:=0;\n         tarjen(i,0);\n      end;\n\n   for i:=1 to n do\n   begin\n      p:=head[i];\n      while (p&lt;&gt;0) do\n      begin\n         j:=edge[p];\n\n         if (ssc[i]&lt;&gt;ssc[j]) then\n         begin\n            inc(outdegree[ssc[i]]);\n         end;\n         p:=tail[p];\n\n\n      end;\n   end;\n\n   node:=0;\n   for i:=1 to totssc do\n      if outdegree[i]=0 then\n      begin\n         if node&lt;&gt;0 then exit(0);\n         node:=i;\n      end;\n   tot:=0;\n   for i:=1 to n do\n      if ssc[i]=node then inc(tot);\n   exit(tot);\n\n\nend;\nbegin\n   sizeedge:=0;\n   fillchar(head,sizeof(head),0);\n   fillchar(tail,sizeof(tail),0);\n   fillchar(edge,sizeof(edge),0);\n   read(n,m);\n   for i:=1 to m do\n   begin\n      read(x,y);\n      addedge(x,y);\n   end;\n   writeln(main);\nend.<\/pre><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u9898\u76ee\u5927\u610f\uff1a\u7ed9\u6709\u5411\u56feG\uff0c\u6c42\u56feG\u4e2d\u6709\u591a\u5c11\u70b9\u80fd\u4ece\u6240\u6709\u8d77\u70b9\u5230\u8fbe \u66b4\u641c\u5fc5T\uff0c\u6545\u672c\u9898\u9700\u8981\u7528Tarjen\u6c42\u6709\u5411\u56fe\u7684\u5f3a\u8fde\u901a\u5206\u91cf [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","footnotes":""},"categories":[3],"tags":[119],"class_list":["post-63","post","type-post","status-publish","format-standard","hentry","category-defaultcategory","tag-connected_graph"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - 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