90分代码：

#include<bits/stdc++.h>
using namespace std;
int t, n, x[50005];

bool check(int m) 
{
	for(int i = m; i <= n; i++) 
	{
		int st = i - m + 1; 
		if(x[st] >= 0 && x[i] <= t)
			return true;
		else if(x[i] <= 0 && abs(x[st]) <= t) 
			return true;
		else if(x[st] <= 0 && x[i] >= 0 && min(abs(x[st]), x[i]) + (x[i] - x[st]) <= t)
			return true;
	}
	return false;
}

int main()
{
	cin >> t >> n;
	for(int i = 1; i <= n; i++)
		cin >> x[i];
	sort(x+1, x+1+n);
	int lt = 0, rt = n;
	while(lt + 1 < rt)
	{
		int mid = (lt + rt) / 2;
		if(check(mid) == true)
			lt = mid;
		else
			rt = mid;
	}
	cout << lt;
	return 0;
}