为什么我这段代码开O2后会有测试点WA呀?

#include<iostream>
#include<cstring>
#include<algorithm>
#define MAXN 5001
using namespace std;
int main() {
	int l, n, a[MAXN];
	memset(a, 0, sizeof(a));
	int min_time, max_time;
	cin >> l >> n;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	if (n == 0) {
		cout << "0 0" << endl;
		return 0;
	}
	sort(a + 1, a + n + 1);
	for (int i = 1; i <= n; i++) {
		min_time = max(min(a[i], l - a[i] + 1), min_time);
	}
	max_time = max(l+1-a[1],a[n]);
	cout << min_time << ' ' << max_time << endl;
	return 0;
}