【USACO 2011 Open】修剪草坪（DP）

 1 #include <cstdio>
 2  
 3 struct node{
 4     int pos;
 5     long long v;
 6 }que[100001];
 7  
 8 int l,r,n,k;
 9 long long e[100001],f[100001],sum,ans(99999999999999);
10 #define min(x,y) (x<y?x:y)
11  
12 int main(void){
13     scanf("%d%d",&n,&k);
14     for(int i=1;i<=n;++i){
15         scanf("%lld",&e[i]);
16         sum+=e[i];
17     }
18     for(int i=1;i<=n;++i){
19         f[i]=que[l].v+e[i];
20         while((l<=r)&&(que[l].pos<i-k))++l;
21         while((l<=r)&&(que[r].v>=f[i]))--r;
22         que[++r].pos=i;
23         que[r].v=f[i];
24     }
25     for(int i=n-k;i<=n;++i)
26         ans=min(ans,f[i]);
27     printf("%lld",sum-ans);
28 }