function max(x,y:longint):longint;
  begin
    if x>y then exit(x)
           else exit(y)
  end;
var
  n,i,j,t,p:longint;
  s1,s2:array[0..5000] of char;
  f:array[0..5000,0..5000] of integer;
begin
  readln(n);
  for i:=1 to n do
  begin
    read(s1[i]);
    s2[n-i+1]:=s1[i];
  end;

  for i:=1 to n do
    for j:=1 to n do
    begin
      f[i,j]:=max(f[i-1,j],f[i,j-1]);
      if s1[i]=s2[j] then f[i,j]:=max(f[i,j],f[i-1,j-1]+1);
    end;

  writeln(n-f[n,n]);
end.

• Re:PASCAL的AC程序（有注解） (594) lqj679ssn 2012-08-05 14:55:26