还是单调栈，维护递减即可，在进行计算，注意要保存前一个比当前数大的数之前有几个比它小。
1 var n,i,j,num,now,tem:longint;
2 ans:int64;
3 stack:array[0..1000001] of longint;
4 h,l:array[0..1000001] of longint;
5 begin
6 readln(n);
7 for i:=1 to n do
8 readln(h[i]);
9 now:=0;
10 ans:=0;
11 //fillchar(l,sizeof(l),1);
12 for i:=1 to n do
13 l[i]:=1;
14 for i:=n downto 1 do
15 begin
16 while (h[i]>stack[now]) and (now<>0) do dec(now);
17 inc(now);
18 stack[now]:=h[i];
19 ans:=ans+n+1-i-now-l[now-1];
20 l[now]:=n+1-i-now;
21 end;
22 write(ans);
23 end.
P1660: [Usaco2006 Nov]Bad Hair Day 乱发节
原文：http://www.cnblogs.com/Kalenda/p/4816967.html