卡了很久了，样例过0pts

#include<bits/stdc++.h>
#define f(q) !q.empty()
using namespace std;
int n,l,r,a[400010],dp[400010],ans=-0x3f3f3f3f;
deque<int> q; 
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n>>l>>r;
    for(int i=0;i<=n;i++){
    	cin>>a[i];
	}
	memset(dp,-63,sizeof(dp));
	dp[0]=0;
	q.push_back(0);
	for(int i=0;i<=n+r-l;i++){
		while(f(q)&&q.front()<i+l-r) q.pop_front();
		//dp[l,r]的最大值可以用来转移dp[l+r]
		//dp[i+l-r,i]的最大值可以用来转移dp[i+l] 
		if(!f(q)) continue;
		dp[i+l]=dp[q.front()]+a[i+l];
		while(f(q)&&dp[q.back()]<dp[i]) q.pop_back();
		q.push_back(i);
	}
	for(int i=n+1;i<=n+r;i++){
		ans=max(ans,dp[i]);
	}
	cout<<ans;
    return 0;
}