Submission #732466

#	Time	Username	Problem	Language	Result	Execution time	Memory
732466		uy842003	Mobile (BOI12_mobile)	C++17	0 / 100	1084 ms	48056 KiB

mobile

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

const double eps = 1e-4, max_sq = 4e18 + 1;

inline bool cmp_less(const double &a, const double &b) {
    return a + eps < b;
}

inline bool cmp_equal(const double &a, const double &b) {
    return abs(a - b) < eps;
}

inline bool cmp_less_equal(const double &a, const double &b) {
    return cmp_less(a, b) || cmp_equal(a, b);
}

inline bool cmp_cor(const pair<double, double> &p1, const pair<double, double> &p2) {
    return cmp_less(p1.first - sqrt(max_sq - p1.second * p1.second), p2.first - sqrt(max_sq - p2.second * p2.second));
}

int main() {
 
    int n;
    double len;
    cin >> n >> len;
    vector<pair<double, double>> cor(n);
    for (int i = 0; i < n; i++)
        cin >> cor[i].first >> cor[i].second;
    // sort(cor.begin(), cor.end(), cmp_cor);
    double l = 0, r = 1e10, m;
    while (cmp_less(l, r)) {
        m = (l + r) / 2;
        vector<pair<double, double>> range, real_range;
        for (int i = 0; i < n; i++) {
            if (!cmp_less_equal(m, abs(cor[i].second))) {
                double dx = sqrt(m * m - cor[i].second * cor[i].second);
                range.push_back({cor[i].first - dx, cor[i].first + dx});
            }
        }
        pair<double, double> cur_range = {-1, -1};
        if (range.size() > 0) cur_range = range[0];
        for (int i = 0; i < range.size(); i++) {
            if (cmp_less_equal(range[i].first, cur_range.second) && cmp_less(cur_range.second, range[i].second))
                cur_range.second = range[i].second;
            if (!cmp_less_equal(range[i].first, cur_range.second) || i + 1 == range.size()) {
                real_range.push_back(cur_range);
                cur_range = range[i];
            }
        }
        bool iok = false;
        for (int i = 0; i < real_range.size(); i++) {
            if (cmp_less_equal(real_range[i].first, 0) && cmp_less_equal(len, real_range[i].second)) {
                iok = true;
                break;
            }
        }
        if (iok)
            r = m;
        else
            l = m + eps;
    }
    cout << setprecision(3) << fixed << r << endl;
 
    return 0;
}

Compilation message (stderr)

mobile.cpp: In function 'int main()':
mobile.cpp:43:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |         for (int i = 0; i < range.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~
mobile.cpp:46:76: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |             if (!cmp_less_equal(range[i].first, cur_range.second) || i + 1 == range.size()) {
      |                                                                      ~~~~~~^~~~~~~~~~~~~~~
mobile.cpp:52:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |         for (int i = 0; i < real_range.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~~~~~~

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