Submission #321594

#	Time	Username	Problem	Language	Result	Execution time	Memory
321594		CSQ31	Mobile (BOI12_mobile)	C++14	100 / 100	794 ms	16108 KiB

mobile

#pragma GCC optimize("Ofast") 
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define sz(a) (int)(a.size())
#define all(a) a.begin(),a.end()
#define lb lower_bound
#define ub upper_bound
#define owo ios_base::sync_with_stdio(0);cin.tie(0);
#define MOD (ll)(1e9+9)
#define INF (ll)(1e18)
#define debug(...) fprintf(stderr, __VA_ARGS__),fflush(stderr)
#define time__(d) for(long blockTime = 0; (blockTime == 0 ? (blockTime=clock()) != 0 : false);\
debug("%s time : %.4fs\n", d, (double)(clock() - blockTime) / CLOCKS_PER_SEC))
typedef long long int ll;
typedef long double ld;
typedef pair<ll,ll> PII;
typedef pair<int,int> pii;
typedef vector<vector<int>> vii;
typedef vector<vector<ll>> VII;
ll gcd(ll a,ll b){if(!b)return a;else return gcd(b,a%b);}
int main()
{
	owo
	int n,L;
	cin>>n>>L;
	vector<ll>x(n),y(n);
	for(int i=0;i<n;i++){
		cin>>x[i]>>y[i];
	}
	double l = 1,r = 1e9;
	while(r-l>1e-4){
		double mid = (l+r)/2;
		double cur = 0;
		for(int i=0;i<n;i++){
			double lf,rg;
			if(y[i] > mid){lf=1e9+5;rg=-1e9;}
			else {double dist = sqrt(mid*mid - y[i]*y[i]);
			      lf = x[i]-dist;
			      rg = x[i]+dist;
			  }
			if(cur >=lf)cur=max(cur,rg);
		}
		if(cur >= L)r=mid;
		else l=mid;
	}
	cout<<fixed<<setprecision(4)<<l;
}

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
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• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
• Subtask 17: 5 / 5
• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
• Subtask 20: 5 / 5
• Subtask 21: 5 / 5