Submission #952351

#	Time	Username	Problem	Language	Result	Execution time	Memory
952351		coolsentenceidontremember	Mobile (BOI12_mobile)	C++17	100 / 100	510 ms	35284 KiB

mobile

#include<bits/stdc++.h>

#define ll long long
#define ld long double
#define ff first
#define ss second
#define db double

using namespace std;

void setIO(string s = ""){
 ios_base::sync_with_stdio(false);
 cin.tie(nullptr);
 cout.tie(nullptr);
 if (s.size()){
	freopen((s+".in").c_str(), "r", stdin);
	freopen((s+".out").c_str(), "w", stdout);
	}
}
ll pow_mod(ll a, ll b, ll m){
	ll res = 1;
	a%=m;
	for (; b; b>>=1, a = (a*a)%m){
		if (b&1) res = (res*a)%m;
	}
	return res;
}

ll pow(ll a, ll b){
	ll res = 1;
	for (; b; b>>=1, a*=a){
		if (b&1) res *= a;
	}
	return res;
}



void GiveMeAnswer(){
   int n;
   db len;
   cin >> n >> len;
   pair<db, db> station[n];
   for (auto &a : station) cin >> a.ff >> a.ss;
   double l = 0, r = 1.5e9;
   while (r-l>1e-4){
   	   db m = (l+r)/2, mx = 0;
   	   for (int i = 0; i < n; i++){
   	   	db p = m*m-station[i].ss*station[i].ss;
   	   	if (p<0) continue;
   	   	p = sqrt(p);
   	   	db start = station[i].ff-p, end = station[i].ff+p;
   	   	if (start<mx) mx = max(mx, end);
		  }
		if (mx>=len) r = m;
		else l = m;
   }
   cout << fixed << setprecision(6) << l << '\n';
}


int main(){
   auto begin = chrono::high_resolution_clock::now();
   setIO();
   int tt = 1;
   //cin >> tt;
   for (int t = 1; t <= tt; t++) GiveMeAnswer();
   auto end = chrono::high_resolution_clock::now();
   // super cool C++ timer
   auto elapsed = chrono::duration_cast<chrono::nanoseconds>(end-begin);
   auto fulltime = elapsed.count()*1e-9;
   cerr << "\n\nExecution time: " << fulltime << " seconds.\n";
   if (fulltime>1) cerr << "TLE!1!!1!!11!!1  C= C= C= C= C=+(;·w·)+";
   else cerr << "You safe brother";

   return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'void setIO(std::string)':
mobile.cpp:16:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |  freopen((s+".in").c_str(), "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:17:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |  freopen((s+".out").c_str(), "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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