Submission #1100989

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100989		hoangteo0103	Mobile (BOI12_mobile)	C++17	100 / 100	734 ms	35400 KiB

mobile

#include "bits/stdc++.h"
using namespace std;
void setIO(string s){
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    if(fopen("trash.in", "r"))
	freopen("trash.in", "r", stdin) , freopen("trash.out", "w", stdout);
}
int main(){
    setIO("hoangteo0103");

    int n, len;
    cin >> n >> len;
    vector<array<double, 2>> a(n);
    for(int i = 0 ; i < n ; i++) cin >> a[i][0] >> a[i][1];

    double ans;

    auto check = [&](double lim) -> bool {
        double prev = 0;
        for(int i = 0 ; i < n ; i++) {
            double edge = sqrt(lim * lim - a[i][1] * a[i][1]) ;
            double l = a[i][0] - edge, r = a[i][0] + edge;
            if(l <= prev)  prev = max(prev, r);
         }
         return prev >= len;
    };
    double l = 0, r = 1.5e9;

    while(r - l > 1e-6) {
        double mid = (l+r)/2;

        if(check(mid)) {
            ans = mid ;
            r = mid;
        } else {
            l = mid;
        }
    }

    cout << fixed << setprecision(6) << ans;
}

Compilation message (stderr)

mobile.cpp: In function 'void setIO(std::string)':
mobile.cpp:7:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 |  freopen("trash.in", "r", stdin) , freopen("trash.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
mobile.cpp:7:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 |  freopen("trash.in", "r", stdin) , freopen("trash.out", "w", stdout);
      |                                    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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