tarjan算法模板

var
{left表示点 root 没离开栈 vis表示点 root 有没有被访问过}
  i,n,m,now,time,color,top:longint;
  v:array[0..10001] of record start:longint;end;
  e:array[0..100001] of record y,next:longint;end;
  dfn,low,stack,encolor:array[0..10001] of longint;
  vis,left:array[0..10001] of boolean;
procedure indata;
  var i,xx,yy,op:longint;
  begin
    time:=0;  color:=0;  top:=0;
    fillchar(e,sizeof(e),0);
    fillchar(v,sizeof(v),0);
    fillchar(dfn,sizeof(dfn),0);
    fillchar(low,sizeof(low),0);
    fillchar(vis,sizeof(vis),0);
    fillchar(left,sizeof(left),1);
    fillchar(encolor,sizeof(encolor),0);
  end;
procedure tarjan(root:longint);
  var te,tv,ttimes:longint;
  begin
    inc(time);
    dfn[root]:=time;  low[root]:=time;
    inc(top);  stack[top]:=root;
    {点 root 入栈 }
    left[root]:=false; vis[root]:=true;
    te:=v[root].start;
    while (te<>0) do
      begin
        tv:=e[te].y;
        if not left[tv] then
          low[root]:=min(low[root],dfn[tv]);
        if not vis[tv] then
          begin
            tarjan(tv);
            low[root]:=min(low[root],low[tv]);
          end;
        te:=e[te].next;
      end;
    if (dfn[root]=low[root]) then
      begin
        inc(color);   tv:=0;
        while (tv<>root) do
          begin
            tv:=stack[top];
            dec(top);
            encolor[tv]:=color;
            left[tv]:=true;
          end;
      end;
  end;