Cod sursa(job #1171580)

Utilizator azkabancont-vechi azkaban Data 15 aprilie 2014 22:35:30
Problema Algoritmul lui Dijkstra Scor 60
Compilator fpc Status done
Runda Arhiva educationala Marime 2.14 kb
Program dijkstra;
type lista = ^celula;
     celula = record
                    nod : longint;
                    cost : longint;
                    pred : lista;
               end;
const INF=2000000000;
var Lda : array [1..50005] of lista;
    r  :lista;
    H,D,poz: array [1..50051] of longint;
    n,i,a,b,c,v,k,aux,p,lungime,o: longint;
    b1,b2 : array[0..1 shl 17] of char;

procedure swap(var x,y : longint);
  var aux : longint;
    begin
       aux:=x;
       x:=y;
       y:=aux;
    end;

procedure  ridica( k : longint);
    begin
        while (k>1) and (D[H[k]]<D[H[k div 2]] ) do begin
                                            swap(H[k],H[k div 2]);
                                            k:=k div 2;
                                                end;
        end;
begin
   assign(input,'dijkstra.in'); settextbuf(input,b1); reset(input);
   assign(output,'dijkstra.out'); settextbuf(output,b2); rewrite(output);
   readln(n,p); aux:=n;
   for i:=1 to p do begin
                        readln(a,b,c);
                        new(r);
                        r^.nod:=b;
                        r^.cost:=c;
                        r^.pred:=lda[a];
                        lda[a]:=r;
                    end;
   for i:=2 to n do D[i]:=INF;
   H[1]:=1;
   poz[1]:=1;
   lungime:=1;
   while lungime>0 do begin
                           v:=H[1];
                           r:=lda[v];
                           H[1]:=H[lungime];
                           lungime:=lungime-1;
   while r<>nil do begin
                       if D[v]+r^.cost<=D[r^.nod] then
                                                  begin
                            D[r^.nod]:=D[v]+r^.cost;
                            lungime:=lungime+1;
                            H[lungime]:=r^.nod;
                            ridica(lungime);
                                                  end;
                           r:=r^.pred;
                    end;
                   end;
   for i:=2 to aux do
                   if D[i]=INF then write(0,' ')
                               else write(D[i],' ');
   close(output);
end.