Submission #67903

#	Time	Username	Problem	Language	Result	Execution time	Memory
67903		thebes	Mobile (BOI12_mobile)	C++14	60 / 100	793 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>
#define sq(x) ((x)*(x))
using namespace std;

const int MN = 1e6+6;
double lo, hi = 3e9, eps = 1e-4;
int N, M, i, j; double mx, dx, m, flag;
pair<int,int> pnt[MN];

signed main(){
	for(scanf("%d%d",&N,&M),i=1;i<=N;i++)
		scanf("%d%d",&pnt[i].first,&pnt[i].second);
	sort(pnt+1,pnt+N+1,[](pair<int,int>i,pair<int,int>j){return i.first<j.first;});
	while(lo+eps<hi){
		m = (lo+hi)/2.0;
		mx = 0;
		for(i=1;i<=N;i++){
			if(abs(pnt[i].second)>m) continue;
			dx=sqrt(sq(m)-sq(1LL*pnt[i].second));
			if(pnt[i].first-dx<=mx) mx=max(mx,pnt[i].first+dx);
		}
		if(mx>=M) hi=m;
		else lo=m+eps;
	}
	printf("%.4lf\n",lo);
	return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:14:25: 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:15:8: 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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