Submission #67570

#	Time	Username	Problem	Language	Result	Execution time	Memory
67570		thebes	Mobile (BOI12_mobile)	C++14	0 / 100	1089 ms	132096 KiB

mobile

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,ssse3,sse3,sse4,popcnt,avx,mmx,abm,tune=native")
#include <bits/stdc++.h>
using namespace std;

const int MN = 1e6+6, MM = 1e9+7;
double lo, hi = MM, eps = 1e-4;
pair<double,int> arr[2*MN];
int N, M, i, j;
pair<int,int> pnt[MN];
typedef pair<double,int> P;
bool cmp(P i,P j){return i.first==j.first?i.second>j.second:i.first<j.first;}
inline bool check(double d){
	for(int i=1;i<=N;i++){
		if(abs(pnt[i].second)>=d){
			arr[2*i-1]=arr[2*i]={-1,-1};
			continue;
		}
		double dx=sqrt(d*d-pnt[i].second*pnt[i].second);
		arr[2*i-1]={pnt[i].first-dx,1};
		arr[2*i]={pnt[i].first+dx,-1};
	}
	sort(arr+1,arr+2*N+1,cmp); int cnt=0;
	for(int i=1;i<=2*N;i++){
		cnt += arr[i].second;
		if(cnt<1&&(i==2*N||arr[i+1].second!=arr[i].second)&&arr[i].first<M&&arr[i].first>0)
			return 0;
	}
	return 1;
}

int main(){
	for(scanf("%d%d",&N,&M),i=1;i<=N;i++)
		scanf("%d%d",&pnt[i].first,&pnt[i].second);
	while(lo+eps<hi){
		double m = (lo+hi)/2;
		if(check(m)) hi=m;
		else lo=m+eps;
	}
	printf("%.4lf\n",lo);
	return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:34:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(scanf("%d%d",&N,&M),i=1;i<=N;i++)
      ~~~~~~~~~~~~~~~~~~~^~~~
mobile.cpp:35:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&pnt[i].first,&pnt[i].second);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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