数据过水，直接暴力就AC了

附上可以AC但明显应该TLE的代码

#include <bits/stdc++.h>
using namespace std;

const int N = 2e5 + 5;
int a[N<<1], dp[N<<1];

int main() {
    int n, l, r;
    scanf("%d %d %d",&n, &l, &r);
    for( int i = 0; i <= n; i++ ) scanf("%d",&a[i]);
    for( int i = 1; i <= n+r; i++ ) dp[i] = -0x3f3f3f3f;

    for( int i = l; i <= n+r; i++ ) 
        for( int j = max( 0, i-r ); j <= i-l; j++ ) dp[i] = max( dp[i], dp[j] + a[i] );

    int res = -0x3f3f3f3f;
    for( int i = n+1; i <= n+r; i++ ) res = max( res, dp[i] );
    printf("%d\n",res);
    return 0;
}