求助，全错。。。

#include<bits/stdc++.h>
using namespace std;
int x[100010],dp[100010];
int main(){
	int n;
	cin >> n;
	int A,B,C;
	cin >> A >> B >> C;
	for (int i = 1; i <= n; i++){
    	int tmp = ((long long)A * i * i + B * i + C) % 20000;//算出x[i] 
    	x[i] = tmp - 10000;	
    	//cout << x[i] << " ";
    }
    for(int i = 0;i <= n;i ++){
		dp[i] = x[i] + max(dp[i + 2],dp[i + 1]);
	}
	cout << dp[n - 1];
	return 0;	
}