POJ2796 Feel Good

 1 #include<set>
 2 #include<cstdio> 
 3 #include<cstdlib> 
 4 #include<cstring> 
 5 #include<iostream>
 6 #include<algorithm>
 7 using namespace std;
 8 const int N = 100010;
 9 const int inf = 2147483647;
10 #define For(i,n) for(int i=1;i<=n;i++)
11 #define Rep(i,l,r) for(int i=l;i<=r;i++)
12 int st[N],A[N],n;
13 long long sum[N];
14 int main(){
15     while(~scanf("%d",&n)){
16         For(i,n){
17             scanf("%d",&A[i]);
18             sum[i]=sum[i-1]+A[i];
19         }
20         A[n+1]=-1;
21         long long ans=-1,tmp;
22         int top=0,l,r;
23         For(i,n+1){
24             while(top!=0&&A[st[top]]>A[i]){
25                 tmp=A[st[top]]*(sum[i-1]-sum[st[top-1]]);
26                 if(ans<tmp){
27                     ans=tmp;
28                     l=st[top-1]+1;
29                     r=i-1;
30                 }
31                 top--;
32             }
33             top++;
34             st[top]=i;
35         }
36         printf("%lld\n%d %d\n",ans,l,r);
37     }
38 }