procedure prim(v0: Integer);
var
  lowcost, closest: array[1..maxn] of Integer;
  i, j, k, Min: Integer;
begin
  for i := 1 to n do
  begin
    lowcost[i] := cost[v0, i];
    closest[i] := v0;
  end;
  for i := 1 to n - 1 do
  begin
    {寻找离生成树最近的未加入顶点k}
    Min := MaxLongint;
    for j := 1 to n do
      if (lowcost[j] < Min) and (lowcost[j] <> 0) then
      begin
        Min := lowcost[j];
        k := j;
      end;
    lowcost[k] := 0; {将顶点k加入生成树}
    {生成树中增加一条新的边k到closest[k]}
    {修正各点的lowcost和closest值}
    for j := 1 to n do
      if cost[k, j] < lwocost[j] then
      begin
        lowcost[j] := cost[k, j];
        closest[j] := k;
      end;
  end;
end;
//delphi/6604