poj2406 Power Strings 2012-01-11

http://162.105.81.212/JudgeOnline/problem?id=2406

 

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求最长重复字串。即将字符串自我匹配，然后字符串长度减去最后一位的next值即为最长重复字串的长度。注意他求的是由多少个最长重复字串组成。

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Program stone;
var i,j:longint;
    s:ansistring;
    b:array[1..1000005]of longint;
Begin
 assign(input,'input.in');reset(input);
  readln(s);
  while s<>'.' do
   begin
     j:=0;
     b[1]:=0;
     for i:=2 to length(s) do
      begin
        while (j>0)and(s[i]<>s[j+1]) do j:=b[j];
        if s[j+1]=s[i] then inc(j);
        b[i]:=j;
      end;
     i:=length(s);
     if i mod (i-b[i])=0 then writeln(i div(i-b[i])) else writeln(1);
     readln(s);
   end;
end.