Submission #217134

#	Time	Username	Problem	Language	Result	Execution time	Memory
217134		dolphingarlic	Mobile (BOI12_mobile)	C++14	90 / 100	1098 ms	35528 KiB

mobile

#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
#define x first
#define y second
using namespace std;

pair<double, double> p[1000000];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n;
    double len;
    cin >> n >> len;
    FOR(i, 0, n) cin >> p[i].x >> p[i].y;

    double l = 1, r = 5e8;
    while (r - l > 1e-3) {
        double mid = (l + r) / 2;

        int cnt = 0;
        double curr = 0;
        FOR(i, 0, n) {
            double delta = sqrt(mid * mid - p[i].y * p[i].y);
            double a = p[i].x - delta, b = p[i].x + delta;
            if (a <= curr) curr = max(curr, b);
        }

        if (curr >= len) r = mid;
        else l = mid;
    }

    cout << fixed << setprecision(4) << l;
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:21:13: warning: unused variable 'cnt' [-Wunused-variable]
         int cnt = 0;
             ^~~

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