浅谈前向星

type rec=record
 pre,en,w:longint;
end;
var n,x,y,w,tot,i,cc:longint;
    a:array[0..10000]of rec;
    head:array[0..10000]of longint;
    p:integer;
procedure adde(u,v,w:longint);
begin
 inc(tot);a[tot].en:=v;
 a[tot].pre:=head[u];head[u]:=tot;
 a[tot].w:=w;
end;
begin
 readln(n);
 fillchar(head,sizeof(head),255);
 fillchar(a,sizeof(a),255); 
 for i:=1 to n do begin
  readln(x,y,w);
  adde(x,y,w);
  writeln(‘Edge ‘,i,‘: ‘,a[i].en,‘ ‘,a[i].pre,‘ ‘,head[i]);
 end;
while true do begin
 readln(x);
 p:=head[x];
 while p>0 do begin
  writeln(a[p].en);
  p:=a[p].pre;
 end;
 writeln;
end;
end.

{链式前向星存储+dijkstra+堆优化}
type rec=record
 pre,en,w:longint;
end;
rec2=record
 id,val:longint;
end;
const inf=233333333;
      maxm=500000;
      maxn=10000;
var i,j,n,m,s,x,y,z,tot,nd:longint;
    d,head:array[-maxn..maxn]of longint;
    a:array[-maxm..maxm]of rec;
    dui:array[0..4*maxm]of rec2;
procedure swap(var a,b:rec2);
var t:rec2;
begin
 t:=a; a:=b; b:=t;
end;
procedure adde(u,v,w:longint);
begin
 inc(tot); a[tot].en:=v;
 a[tot].pre:=head[u];
 head[u]:=tot;
 a[tot].w:=w;
end;
procedure swap(var a,b:longint);
var t:longint;
begin t:=a;a:=b;b:=t;end;
procedure up(x:longint);//将一个结点“上浮”
begin
  while x>1 do begin //没有上浮到最顶层
    if dui[x].val>dui[x div 2].val then break;//如果上方的结点小于此节点，则暂停上浮
    swap(dui[x],dui[x div 2]);//交换上方结点与此结点
    x:=x div 2;
  end;
end;
procedure down(x:longint);//将一个节点“下沉”
  var y:longint;
begin
  while x<nd do begin
    y:=x+x;//y是x的左儿子
    if y>nd then break;//x已经沉到底部
    if (y<nd)and(dui[y+1].val<dui[y].val) then inc(y);//如果x存在右儿子，且右儿子比左儿子小，则将y赋值到右儿子
    if dui[x].val<=dui[y].val then break;//若两个儿子中的较小值仍然比x大，则停止下沉
    swap(dui[x],dui[y]);//下沉
    x:=y;
  end;
end;
function pop():longint;
begin
  pop:=dui[1].id;
  swap(dui[1],dui[nd]);//将最后的结点（保证其没有儿子）与最顶端交换
  dec(nd);
  down(1);//下沉顶端
end;
procedure dijkstra(v0:longint);
var i,j,k,minn,u,v,p:longint;
    vis:array[-maxn..maxn]of boolean;
begin
 fillchar(vis,sizeof(vis),false);
 for i:=1 to n do d[i]:=inf;
 d[v0]:=0;
 dui[1].val:=0;
 dui[1].id:=v0;
 nd:=1;
 for i:=1 to n do begin
  u:=pop();
  while vis[u] and (nd>0) do u:=pop();
  vis[u]:=true;
  p:=head[u];
  while p>0 do begin
   v:=a[p].en;
   if (not vis[v]) and(d[u]+a[p].w<d[v]) then begin
    d[v]:=d[u]+a[p].w;
    inc(nd);
    dui[nd].id:=v;
    dui[nd].val:=d[v];
    up(nd);
   end;
   p:=a[p].pre;
  end;
 end;
end;
begin
 readln(n,m,s);
 for i:=1 to m do begin
  readln(x,y,z);
  adde(x,y,z);
 end;
 dijkstra(s);
 for i:=1 to n do
 if d[i]=inf then write(2147483647,‘ ‘)else write(d[i],‘ ‘);
 writeln;
end.