csp校门外的树

#include<iostream>
#include<cstdlib>
#include<algorithm>
#include<vector>

using namespace std;

const int N = 1010, M = 1e5 + 10, MOD = 1e9 + 7;
int n;
int a[N];
int f[N]; //f[i] = a[0] ~ a[i] 方案数
bool st[M];
vector<int> factor[M];
void get_factor(vector<int> *factor, int m)
{
	for (int i = 1; i < m; i++)
	{
		for (int j = i * 2; j < m; j += i)
			factor[j].push_back(i);
	}
 }

int get_sum(int *a, int index)
{
	//printf("
index:%d
", index);
	memset(st, 0, sizeof(st));
	if (0 == index) return 1;
	long long res = 0;
	for (int i = index - 1; i >= 0; i--) {
		int d = a[index] - a[i], cnt = 0;
		for (auto k : factor[d])
		{
			if (!st[k])
			{
				//printf("k:%d
", k);
				cnt++;
				st[k] = true;
			}
		}
		st[d] = true;
		res += ((long long)f[i] * cnt % MOD);
		res %= MOD;
		//printf("res:%d
", res);

	}
	return (int)(res % MOD);
}

int main() {
	get_factor(factor, M);
	//return 0;

	scanf("%d", &n);
	for (int i = 0; i < n; i++)
	{
		scanf("%d", a + i);
		f[i] = get_sum(a, i) % MOD;
		//printf("f_%d:%d
",i, f[i]);

	}
	printf("%d
", f[n - 1]);
	return 0;
}