1 #include <cstdio>
 2 #include <cstring>
 3 #include <cmath>
 4 #include <cstdlib>
 5 #include <queue> 
 6 #include <iostream>
 7 using namespace std ; 
 8 
 9 const int maxn = 200011 ; 
10 struct node{
11     int val,id ; 
12 };
13 deque <node> Q ; 
14 int n,l,r,x,ans ; 
15 int a[2*maxn],f[2*maxn] ; 
16 
17 inline int read() 
18 {
19     char ch = getchar() ; 
20     int x = 0 , f = 1 ; 
21     while(ch<‘0‘||ch>‘9‘) { if(ch==‘-‘) f = -1 ;ch = getchar() ; } 
22     while(ch>=‘0‘&&ch<=‘9‘) x = x*10+ch-48,ch = getchar() ; 
23     return x*f ; 
24 }
25 
26 int main() 
27 {
28     n = read() ;    l = read() ;    r = read() ; 
29      for(int i=0;i<=n;i++) 
30         a[ i ] = read() ; 
31     node p ; 
32     for(int i=l;i<=n+r+3;i++) 
33     { 
34         x = i-l ; 
35         while(!Q.empty()&&f[ x ] >= Q.back().val ) Q.pop_back() ; 
36         p.val = f[ x ] ; 
37         p.id = x ; 
38         Q.push_back( p ) ; 
39         while(!Q.empty()&& i-Q.front().id>r ) Q.pop_front() ;     // >     这里是   跳过  r段  如果  包括初始 节点时  r+1段  
40         f[ i ] = Q.front().val + a[ i ] ; 
41 
42     }
43     for(int i=n+1;i<=n+r+1;i++) if(f[ i ]>ans)  ans = f[ i ] ; 
44     printf("%d\n",ans) ; 
45     
46     return 0 ; 
47 }