const
     maxn=5000;
var
     a:array[1..maxn] of char;
     f1,f2:array[0..maxn] of longint;
     i,j,k,l,m,n,t,s:longint;

function max(a,b:longint):longint;
begin
 if a>b then max:=a else max:=b;
end;

begin
 readln(n);
 for i:=1 to n do
  read(a[i]);
 readln;
 fillchar(f1,sizeof(f1),0);
 fillchar(f2,sizeof(f2),0);
 for i:=1 to n do begin
  for j:=1 to n do
   if a[i]=a[n-j+1] then f2[j]:=f1[j-1]+1 else
    f2[j]:=max(f2[j-1],f1[j]);
  f1:=f2;
 end;
 writeln(n-f2[n]);
end.

• 解释一下啊....~难道添数据了？那也应该rej啊~ (563) palmtenor 2005-06-09 18:23:04