Submission #374762

#	Time	Username	Problem	Language	Result	Execution time	Memory
374762		wzy	Mobile (BOI12_mobile)	C++17	100 / 100	668 ms	27628 KiB

mobile

#include <bits/stdc++.h>
using namespace std;
const int N = 1000005;
int n , L;
pair<int,int> v[N];

double f(double mid){
	double cur = 0.00;
	for(int i = 1 ; i <= n; i ++){
		double len = sqrt(mid*mid - 1.00 * (1ll * v[i].second)* (1ll * v[i].second));
		if(cur >= (1.00 * v[i].first - len))
			cur = max(cur , 1.00*v[i].first + len);
	}
	return cur >= L;
}

int32_t main(){
	scanf("%d%d" , &n , &L);
	for(int i = 1; i <= n; i ++){
		scanf("%d%d" , &v[i].first , &v[i].second);
	}
	sort(v + 1 , v + 1 + n);
	double l = 0.000 , r = 4e9;
	while(r-l > 1e-6){
		double mid = l + (r-l)/2;
		if(f(mid))
			r = mid;
		else
			l = mid;
	}
	printf("%.6lF" , l);
}

Compilation message (stderr)

mobile.cpp: In function 'int32_t main()':
mobile.cpp:18:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   18 |  scanf("%d%d" , &n , &L);
      |  ~~~~~^~~~~~~~~~~~~~~~~~
mobile.cpp:20:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   20 |   scanf("%d%d" , &v[i].first , &v[i].second);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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