记录编号	607	评测结果	AAATWAAT
题目名称	[NOIP 2002]字串变换	最终得分	62
用户昵称	zhai	是否通过	未通过
代码语言	Pascal	运行时间	2.176 s
提交时间	2008-07-19 21:26:52	内存使用	0.11 MiB

program str;
  const
    rmax=6;
    limit=10;
    smax=20;
  var
    rule:array[1..rmax,1..2]of string[smax];
    st,nd:string;
    best:integer;
    rulemax:integer;
    procedure init;
      var
        temp:string;
      begin
        assign(input,'string.in');reset(input);
        assign(output,'string.out');rewrite(output);
        readln(temp);
        st:=copy(temp,1,pos(' ',temp)-1);
        nd:=copy(temp,pos(' ',temp)+1,length(temp)-pos(' ',temp));
        rulemax:=0;
        while not eof do begin
          inc(rulemax);
          readln(temp);
          rule[rulemax,1]:=copy(temp,1,pos(' ',temp)-1);
          rule[rulemax,2]:=copy(temp,pos(' ',temp)+1,length(temp)-pos(' ',temp));
        end;
      end;
    procedure try(now:string;step:integer);
      var
        k,temp:integer;
        stemp:string;
      begin
        for k:=1 to rulemax do begin
         if length(now)+length(rule[k,2])-length(rule[k,1])<115
           then begin
             temp:=pos(rule[k,1],now);
             if temp<>0 then begin
               stemp:=copy(now,1,temp-1)+rule[k,2]
               +copy(now,temp+length(rule[k,1]),115);
               if stemp=nd then begin
                 if step<best then best:=step;
               end
               else if step<best then try(stemp,step+1);
             end;
           end;
        end;
      end;
  begin
    init;
    best:=limit+1;
    try(st,1);
    if best<limit then writeln(best)
    else writeln('NO ANSWER!');
  end.