Cattle off winter training camp 5 - B

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Topic is relatively simple (but I'm up on the understanding become DP) recently DP top of the ...

Accuracy should be half card that causes just over 85%, to improve further improvements down ...

The following is the third of the solution:
(two points and a third difference lies only run on a monotonic sections, can be run on a single-peak intervals, the third constant is about two minutes but they are 2 to 3 times? the complexity of logn)

Direct-third to coordinate, normal-third of ideas on the line

Here write about one-third of the time interval must let about (my habit is l and r) from their recent move to the flag (or else if the value of the most likely between two flags will hang)

AC Code:

#include <iostream>
#include <queue>
#include <cstring>
#include <cmath>
#include <algorithm>
#define MAX 200020 
#define ll long long
#define mod 1000000007
using namespace std;

struct node{
	double x,y;
}p[MAX];
int n;
double search(double a)
{
	double ans=-1;
	for(int i=0;i<n;i++)
	{
		double now=sqrt(p[i].y*p[i].y+(p[i].x-a)*(p[i].x-a));
		if(now>ans)
		ans=now;
	}
	return ans;
}

int main()
{

	cin>>n;
	for(int i=0;i<n;i++)
		cin>>p[i].x>>p[i].y;
	double l=-20000;
	double r=20000;
	while(l+1e-8<r)
	{
		double mid=(l+r)/2;
		double midmid=(r+mid)/2;
		if(search(mid)>search(midmid))
		l=mid;
		else
		r=midmid;
	}
	printf("%.6lf",search(l));
	return 0;
}

The solution is to write on the topic

		mid=left+(right-left)/2;
        midmid=mid+(right-mid)/2;

This slightly to avoid overflow ... learned (but obviously do not need this title)