Submission #1353603

#	Time	Username	Problem	Language	Result	Execution time	Memory
1353603		Owstin	Mobile (BOI12_mobile)	C++20	4 / 100	515 ms	32508 KiB

mobile

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <utility>
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);
#define pb push_back
#define all(x) begin(x), end(x)
#define space " "
#define TEST_CASES int a; cin >> a; for (int i = 0; i < a; i++) {solve(); cout << endl;}
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());

void solve() {
    int n; double l; cin >> n >> l;
    vector<pair<double, double>> vec;
    for (int i = 0; i < n; i++) {
        int x, y; cin >> x >> y;
        if (vec.empty() || x != vec.back().first) {
            vec.pb({x, y});
        }
        else if (x == vec.back().first) {
            if (abs(y) < abs(vec.back().second)) {
                vec.back().second = y;
            }
        }
    }
    n = vec.size();
    sort(all(vec));
    double lo = 0; double hi = 1e10;
    for (int k = 0; k < 100; k++) {
        double mid = (lo + hi) / 2;
        stack<pair<double, double>> s;
        for (int i = 0; i < n; i++) {
            if (abs(vec[i].second) - mid > 0) {
                continue;
            }
            double dist = sqrt(mid * mid - vec[i].second * vec[i].second);
            pair<double, double> curr = {vec[i].first - dist, vec[i].first + dist};
            while (!s.empty() && s.top().first > curr.first) {
                s.pop();
            }
            if (s.empty() || curr.second > s.top().second) {
                s.push(curr);
            }
        }
        bool flag = true; double point = l;
        while (!s.empty()) {
            if (s.top().second < point) {
                flag = false;
            }
            point = s.top().first;
            s.pop();
        }
        if (flag && point <= 0) {
            hi = mid;
        }
        else {
            lo = mid;
        }
    }
    cout << hi;
}

int main() {
    FAST_IO;
    //freopen("snowboots.in", "r", stdin);
    //freopen("snowboots.out", "w", stdout);
    //TEST_CASES;
    solve(); cout << endl;
    /*int a; cin >> a;
    for (int i = 1; i <= a; i++){
        cout << "Case #" << i << ": ";
        solve();
        cout << endl;
    }*/
}

• Subtask 1: 4 / 4
• Subtask 2: 0 / 4
• Subtask 3: 0 / 4
• Subtask 4: 0 / 4
• Subtask 5: 0 / 4
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• Subtask 21: 0 / 5