SubstackWA

#include<bits/stdc++.h>
using namespace std;
long n,l,r,head=0,tail=0,q[200006],a[200006],dp[200006];
int main() {
    for(int i=1; i<=n; i++) {
        dp[i]=-2e9;
    }
    dp[0]=0;
    scanf("%ld%ld%ld",&n,&l,&r);
    for(int i=0; i<=n; i++) {
        cin>>a[i];
        q[i]=a[i];
    }
    long ans=-2e9;
    for (int i=l; i<=n; i++) {
        while (head<=tail&&q[head]<i-(r)) head++;
        while (head<=tail&&dp[q[tail]]<=dp[i-l])
            tail--;
        q[++tail]=i-l;
        dp[i]=max(dp[i],dp[q[head]]+a[i]);
        if(i+r>n) ans=max(ans,dp[i]) ;
    }
    printf("%ld",ans);
    return 0;
}

…… QwQ