ac1151.pas

同济大学 Online在线题库 AC源代码合集 程序设计竞赛必看资料

program tju1151;
var
  count:array[0..63]of longint;
  n,i,j,c:longint;
  s:string;
  ans:int64;
begin
  readln(n);
  for i:=1 to n do begin
    readln(s);
    c:=0;
    for j:=2 to 7 do
      c:=c*2+ord(s[j]<>s[j-1]);
    inc(count[c]);
  end;
  for i:=0 to 63 do
    ans:=ans+int64(count[i])*(count[i]-1) shr 1;
  writeln(ans);
end.