теория графов, определение вершин лежащих на min пути

program MDP;
uses crt;
var
 G,F1,F2,F3,F4: set of byte;
R,M,S,B: array [1..20,1..20] of integer;
Y: array [1..10] of integer;
i,j,k,n,C,V: integer;
begin
 clrscr;
 G:=[1,2,3,4];
 F1:=[2,3,4];
 F2:=[1,3,4];
 F3:=[1,2,4];
 F4:=[1,2,3];
 
 for i:=1 to 4 do
for j:=1 to 4 do begin
 if j in F1 then R[1,j]:=1
  else R[1,j]:=0;
 if j in F2 then R[2,j]:=1
  else R[2,j]:=0;
 if j in F3 then R[3,j]:=1
  else R[3,j]:=0;
 if j in F4 then R[4,j]:=1
  else R[4,j]:=0;
end;
writeln('vvedite n');
read(n);
 writeln('matrica smeznosti R->');
 for i :=1 to n do begin
 for j:=1 to n do
  write(R[i,j],' ');
  writeln;
 end;
 
 for i:=1 to n do
for j:=1 to n do begin
if R[i,j]=1 then  begin
write('Vvedite ves dugi-> ');
readln(V);
S[i,j]:=V;
end;
end;
writeln('matrica rasstoyanii L ->');
 for i :=1 to n do begin
 for j:=1 to n do
  write(S[i,j],' ');
  writeln;
 end;
 
for j:=1 to n do
B[j,1]:=0;
for i:=2 to n do
for j:=1 to n do
B[j,i]:=-99;
 
j:=1;
repeat j:=j+1;
 
k:=0;
for i:=1 to n do
if S[i,j]>0 then begin
k:=k+1;
Y[k]:=B[j-1,i]+S[i,j];
end;
 
C:=-99; {minus beskone4nost}
for n:=1 to k do
if Y[n]<C then C:=Y[n];
 
for i:=j to n do
B[i,j]:=C;
until j=4;
 
 writeln('opredelenie dliny minimalnogo puti->');
 
 for j:=1 to n do begin
 for i:=1 to n do
  write(B[j,i],'   ');
  writeln;
  end;
 readln;
End.