hdu1506 dp

 1 //Accepted    1428 KB    62 ms
 2 //
 3 #include <cstdio>
 4 #include <cstring>
 5 #include <iostream>
 6 using namespace std;
 7 const int imax_n = 100005;
 8 int l[imax_n];
 9 int r[imax_n];
10 int a[imax_n];
11 int n;
12 void Dp()
13 {
14     l[1]=1;
15     a[0]=-1;
16     for (int i=2;i<=n;i++)
17     {
18         int t=i;
19         while (a[i]<=a[t-1])
20         {
21             t=l[t-1];
22         }
23         l[i]=t;
24     }
25     r[n]=n;
26     a[n+1]=-1;
27     for (int i=n-1;i>=1;i--)
28     {
29         int t=i;
30         while (a[i]<=a[t+1])
31         {
32             t=r[t+1];
33         }
34        r[i]=t;
35     }
36     __int64 ans=0;
37     for (int i=1;i<=n;i++)
38     {
39         if ((__int64 )a[i]*(r[i]-l[i]+1)>ans)
40         ans=(__int64 )a[i]*(r[i]-l[i]+1);
41     }
42     printf("%I64d\n",ans);
43 }
44 int main()
45 {
46     while (scanf("%d",&n),n)
47     {
48         for (int i=1;i<=n;i++)
49         scanf("%d",&a[i]);
50         Dp();
51     }
52     return 0;
53 }

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