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最新推荐文章于 2024-04-30 00:42:32 发布

原创最新推荐文章于 2024-04-30 00:42:32 发布 · 879 阅读

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本文介绍了一种使用记录型结构和堆数据结构解决程序设计竞赛中路径选择问题的方法，通过不断寻找当前最优路径并更新全局最短路径总和，最终求得所有节点间连接的最小成本。

program as;
type
  t1     =record
  wz,shu :longint;
end;
var
  n,heapsize,t   :longint;
  sum,totel    :longint;
  a            :array[1..701,0..701] of longint;
  bool         :array[1..490001] of boolean;
  heap         :array[1..490001] of t1;
procedure duru;
var
  i,j:longint;
begin
  read(n);   t:=1;
  totel:=0;
  heapsize:=0;
  fillchar(bool,sizeof(bool),false);
  bool[1]:=true;
  for i:=1 to n do
    for j:=1 to n do
      read(a[i,j]);
end;
procedure insert(x,x1:longint);
var
  l:longint;
begin
  inc(heapsize);
  l:=heapsize;
  while (l<>1)and(x<heap[l div 2].shu) do
    begin
      heap[l]:=heap[l div 2];
      l      :=l div 2;
    end;
  heap[l].shu:=x;
  heap[l].wz :=x1;
end;
procedure delete(i:longint);
var
  cl:longint;
  x :t1;
begin
  x:=heap[heapsize];
  dec(heapsize);
  cl:=2*i;
  while cl<=heapsize do
    begin
      if (cl<heapsize) and (heap[cl].shu>heap[cl+1].shu) then
      inc(cl);
      if x.shu<heap[cl].shu then break;
      heap[i]:=heap[cl];
      i:=cl;
      cl:=i*2;
    end;
  heap[i]:=x;
end;
procedure im;
var
  q             :boolean;
  jl,i1,i,j   :longint;
begin
  for i1:=1 to n do
    begin
      i:=t;
      q:=false;
      for j:=1 to n do
        if (a[i,j]<>0)and(not bool[j])and(i<>j) then
          begin
            q:=true;
            insert(a[i,j],j);
          end;
        if q then
          begin
            inc(totel);
            bool[heap[1].wz]:=true;
            sum             :=sum+heap[1].shu;
            if totel=n-1 then exit;
            t:=heap[1].wz;
            while bool[heap[1].wz] do
            delete(1);
          end;
     end;
end;
begin
  assign(input,'t1.in1');
  reset(input);
  assign(output,'t1.out1');
  rewrite(output);
  duru;
  im;
  writeln(sum);
  close(input);
  close(output);
end.