```pascal
var n,t,i:longint;
cnt,sum:int64;
begin
readln(n);
for i:=1 to n do
begin
read(t);
if t=1 then inc(cnt)
else sum:=sum+cnt;
end;
writeln(sum);
end.
```
如此简单
by 土间太平 @ 2018-07-27 12:56:48
A了,谢谢
by ylxmf2020 @ 2018-07-27 12:57:14
我唯一一道切得动的黑题
by 土间太平 @ 2018-07-27 12:58:47
您是在翻译题解吗?
by 祈佑·绾青鸢 @ 2018-07-27 12:58:51
大哥,水题代码撞都撞得到一起的好伐
by 土间太平 @ 2018-07-27 13:02:10
@[永恒·天命](/space/show?uid=52581)
by 土间太平 @ 2018-07-27 13:02:13
贪心,超级简%%%
by ylxmf2020 @ 2018-07-27 13:12:02
贪心,超级简%%%
by 该起什么名字 @ 2018-07-27 13:39:14
@[chen_zhe](/space/show?uid=8457) %%%
by ChthollyTree @ 2018-07-27 13:43:17
太强了%%%
by VenusM1nT @ 2018-07-27 13:45:22