读入 时时留意，处处小心  
  pascal 伤不起  附代码
procedure init;
var tmp,i:longint;
    ch:char;
begin
  readln(m,l);
  fillchar(a,sizeof(a),0);
  a[m+2]:=-1;
  for i:=1 to m-1 do
    begin
      read(ch);
      case ch of
        '-':begin read(tmp);a[i]:=-tmp; end;
        '+':begin read(tmp);a[i]:=tmp; end;
        'L':a[i]:=-100000;
        '0':a[i]:=0;
      end;
      read(ch);
    end;
  if m<>0 then begin
    read(ch);
      case ch of
        '-':begin read(tmp);a[m]:=-tmp; end;
        '+':begin read(tmp);a[m]:=tmp; end;
        'L':a[m]:=-100000;
        '0':a[m]:=0;
      end;
    readln;
    end;
end;