【POJ】3250 Bad Hair Day

 1 #include<cstdio>

 2 typedef __int64 LL;

 3 #define MAXN 80010

 4 int st[MAXN];

 5 int main()

 6 {

 7     LL ans;

 8     int n,i,x,top;

 9     while(~scanf("%d",&n))

10     {

11         for(top=-1,ans=i=0;i<n;i++)

12         {

13             scanf("%d",&x);

14             for(;top>-1&&st[top]<=x;top--);

15             st[++top]=x;

16             ans+=top;

17         }

18         printf("%I64d\n",ans);

19     }

20     return 0;

21 }