Submission #231346

#	Time	Username	Problem	Language	Result	Execution time	Memory
231346		DodgeBallMan	Mobile (BOI12_mobile)	C++14	100 / 100	745 ms	35288 KiB

mobile

#include <bits/stdc++.h>

using namespace std;

const int N = 1e6 + 10;
int n;
double L, x[N], y[N];

bool check( double mid ) {
    double mx = 0;
    for( int i = 1 ; i <= n ; i++ ) {
        double len = sqrt( mid*mid - y[i]*y[i] );
        double le = x[i] - len, ri = x[i] + len;
        if( le <= mx ) mx = max( mx, ri );
    }
    return ( mx >= L );
}
int main()
{
    scanf("%d %lf",&n,&L);
    for( int i = 1 ; i <= n ; i++ ) scanf("%lf %lf",&x[i],&y[i]);
    double l = 1, r = 5e8;
    while( r - l > 0.001 ) {
        double mid = ( l + r ) / 2.0;
        if( check( mid ) ) r = mid;
        else l = mid;
    }
    printf("%.4lf",l);
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:20:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %lf",&n,&L);
     ~~~~~^~~~~~~~~~~~~~~~
mobile.cpp:21:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for( int i = 1 ; i <= n ; i++ ) scanf("%lf %lf",&x[i],&y[i]);
                                     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
• Subtask 7: 5 / 5
• Subtask 8: 5 / 5
• Subtask 9: 5 / 5
• Subtask 10: 5 / 5
• Subtask 11: 5 / 5
• Subtask 12: 5 / 5
• Subtask 13: 5 / 5
• Subtask 14: 5 / 5
• 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