如何在Pascal中实现trie数据结构?

时间:2013-01-10 15:50:27

标签: dictionary pascal trie

我想在Pascal中试一试。我开始是但我插入方法无法正常工作。这是该计划的一部分:

type PVrchol = ^Vrchol;
     Vrchol = record
       endOfTheWord:boolean;
       deti:array['a'..'z'] of PVrchol;
     end;
var trie:PVrchol;

FUNCTION getChildnode(current:PVrchol;k:char):PVrchol;
    Begin
      if current^.deti[k]<>nil then
         getChildnode:=current^.deti[k]
       else
         getChildNode:=nil;
    End;

PROCEDURE insertWord(word:string;var trie:PVrchol);
var i:integer;
  current, childNode:PVrchol;
Begin
  current:=trie;
  childNode:=current;
  for i:=1 to Length(word) do begin
      childNode:=getChildnode(current,word[i]);
      if childNode=nil then begin
        new(childNode);
        current^.deti[word[i]]:=childNode;
      end;
      current:=childNode;
  end;
  current^.endOfTheWord:=true;
End;
BEGIN
new(trie);
//there are some methods reading the words from input, and calling the insertWord procedure.
END.

insertWord过程总是得到一个单词,所以参数不会是“”。

1 个答案:

答案 0 :(得分:0)

问题可能是记录不会像类一样自动归零?尝试添加

fillchar(childnode,sizeof(childnode),#0);  

在new(childnode)之后