Submission #864761

#	Time	Username	Problem	Language	Result	Execution time	Memory
864761		nhatvpm	Mobile (BOI12_mobile)	C++17	100 / 100	565 ms	35048 KiB

mobile

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ld=long double;

void setIO(string name) {
	freopen((name+".in").c_str(),"r",stdin);
	freopen((name+".out").c_str(),"w",stdout);
}

void solve(){
	ll n,l;
	cin>>n>>l;
	vector<ll> x(n),y(n);
	for (int i=0;i<n;i++) cin>>x[i]>>y[i];
	ld lo=0,hi=3e9,eps=1e-9;
	while (hi-lo>eps){
		ld mid=(lo+hi)/2,s=0;
		for (int i=0;i<n;i++){
			if (mid<abs(y[i])) continue;
			ld d=sqrt(pow(mid,2)-pow(y[i],2));
			ld a=x[i]-d,b=x[i]+d;
			if (a<=s) s=max(s,b);
		}
		if (s>=l) hi=mid;
		else lo=mid;
	}
	cout<<fixed<<setprecision(15)<<lo;
	
	
	
	
	
	
	
}


int main(){
	//setIO("");
	ios_base::sync_with_stdio(0);
    cin.tie(0);
	int tc=1;
	//cin>>tc;
	while (tc--){
		solve();
	}
}

Compilation message (stderr)

mobile.cpp: In function 'void setIO(std::string)':
mobile.cpp:8:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |  freopen((name+".in").c_str(),"r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:9:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |  freopen((name+".out").c_str(),"w",stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
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