codevs1506 Messenger (Kosaraju algorithm)

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One () dozen [] watched all night .....

/*finding strong connected component Kosaraju algorithm side-table chart positive and negative structure two graphs run both sides to write down the order of the stack and the specific information of each strong connected component.*/#include<iostream>#include<cstring>#include<cstdio>#include<stack>#defineMAXN 1010#defineMaxx 10010using namespacestd;intn,m,num,head1[maxn],head2[maxn],f[maxn],cnt;intFlag[maxn],ans[maxn][maxn];stack<int>s;structnode{intU,v,per;} E1[maxx],e2[maxx];voidInput ()//The input composition E1 positive E2 as the inverse{    intI,x,y; CIN>>n>>m;  for(i=1; i<=m;i++) {cin>>x>>y; Num++; E1[NUM].U=x; E1[NUM].V=y; E1[num].per=Head1[x]; HEAD1[X]=num; E2[NUM].U=y; E2[NUM].V=x; E2[num].per=Head2[y]; Head2[y]=num; }}voidDFS1 (intk) {F[k]=1;  for(intP=head1[k];p; p=e1[p].per) {          if(!F[E1[P].V])      DFS1 (E1[P].V); } s.push (k);//record entry stack sequence}voidDFS2 (intk) {F[k]=1; ans[cnt][++ans[cnt][0]]=k;//Note each point of the first CNT strong connected component     for(intI=head2[k];i;i=e2[i].per)if(f[e2[i].v]==0) DFS2 (E2[I].V); if(ans[cnt][0]>1) flag[k]=1;//if the size of the first CNT strongly connected component is >1 then x belongs to a strongly connected component}voidKosaraju () {memset (f),0,sizeof(f));  for(intI=1; i<=n;i++)//run the first time DFS each point into the stack sequentially      {          if(f[i]==0) DFS1 (i); } memset (F,0,sizeof(f));  while(!s.empty ())//run the second time. DFS marks whether each point belongs to a strong connected component and calculates the quantity      {          inttmp=S.top ();          S.pop (); if(f[tmp]==0) {CNT++;//count Strong connected componentsDFS2 (TMP); }      }}voidPrintf () { for(intI=1; i<=n;i++)      if(flag[i]==1) cout<<"T"<<Endl; Elsecout<<"F"<<Endl;}intMain () {Input ();    Kosaraju ();    Printf (); return 0;}

codevs1506 Messenger (Kosaraju algorithm)