race time - ternary search

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 100005;
int speed[MAXN], dist[MAXN];
int main()
{
	// freopen("input.txt", "r", stdin);
	ios_base::sync_with_stdio(0);
	int n,k;
	cin>>n>>k;
	for (int i = 0; i < n; ++i)
	{
		cin>>speed[i]>>dist[i];
	}
	long double lo = 0.0, hi = k;
	for (int i = 0; i < 200; ++i)
	{
		long double m1 = lo+((hi-lo)/3.0);
		long double m2 = hi-((hi-lo)/3.0);
		long double min1 = 1e20, max1 = -1e20, min2 = 1e20, max2 = -1e20;
		for (int i = 0; i < n; ++i)
		{
			long double val = (speed[i]*m1) + dist[i];
			min1 = min(min1, val);
			max1 = max(max1, val);
			val = (speed[i]*m2) + dist[i];
			min2 = min(min2, val);
			max2 = max(max2, val);
		}
		max1-=min1;
		max2-=min2;
		if(max1 < max2)
			hi = m2;
		else
			lo = m1;
	}
	long double min1 = 1e20, max1 = -1e20;
	for (int i = 0; i < n; ++i)
	{
		long double val = (speed[i]*lo) + dist[i];
		min1 = min(min1, val);
		max1 = max(max1, val);
	}
	double ans = max1-min1;
	cout.precision(6);
	cout<<fixed<<ans<<"\n";
	return 0;
}