Submission #112589

#	Time	Username	Problem	Language	Result	Execution time	Memory
112589		zoooma13	Mobile (BOI12_mobile)	C++14	0 / 100	1082 ms	10744 KiB

mobile

#include <bits/stdc++.h>
using namespace std;

#define MAX_N 1000006

int n ,l;
int x[MAX_N] ,y[MAX_N];

bool can(double X)
{
    double mx = 0;
    for(int i=0; i<n; i++){
        if(y[i]-X > 1e-6)
            continue;
        double len = sqrt((X*X)-(1.0*y[i]*y[i]));
        if(x[i]-len-mx > 1e-6)
            return 0;
        mx = max(mx ,x[i]+len);
    }
    return (mx >= l);
}

int main()
{
    scanf("%d%d",&n,&l);
    for(int lx=-2e9 ,i=0; i<n; i++)
    {
        scanf("%d%d",&x[i],&y[i]) ,y[i] = abs(y[i]);
        if(lx == x[i]){
            y[i-1] = min(y[i-1] ,y[i]);
            i-- ,n--;
        }lx = x[i];
    }

    double st = 0 ,en = 1e18 ,mid;
    for(int ee=200; ee; ee--){
        mid = (st+en)/2;
        if(can(mid))
            en = mid;
        else
            st = mid;
    }

    cout << fixed << setprecision(6) << en << endl;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&l);
     ~~~~~^~~~~~~~~~~~~~
mobile.cpp:28:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&x[i],&y[i]) ,y[i] = abs(y[i]);
         ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~

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