Submission #1312193

#	Time	Username	Problem	Language	Result	Execution time	Memory
1312193		hansen	Mobile (BOI12_mobile)	C++20	100 / 100	385 ms	15940 KiB

mobile

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define int long long
#define fi first
#define se second
#define test(v)            \
    for (auto &x : (v)) {       \
        cout << x << " ";       \
    }                           \
    cout << "\n";
#define test2d(v) \
    for (int i = 0; i < (int)v.size(); i++) { \
        for (int j = 0; j < (int)v[i].size(); j++) { \
            cout << v[i][j] << " "; \
        } \
        cout << '\n'; \
    }
#define pb push_back
vector<pair<int, int>> dirs = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
mt19937 rng((int)chrono::steady_clock::now().time_since_epoch().count());
int hashp = uniform_int_distribution<int>(10, 1e9)(rng);
int hashm1 = 1e9+7;
int hashm2 = 1e9+9;
int MOD = 1e9 + 7;

void solve(){
    int n, L;
    cin >> n >> L;
    vector<array<int, 2>> a(n);
    for(int i = 0; i < n; i++){
        cin >> a[i][0] >> a[i][1];
    }
    long double l = 0, r = 2e9;
    while(r - l > 1e-7){
        long double m = (l+r)/2;
        long double cur = 0;
        for(auto[x, y]: a){
            if (abs(y) > m) continue;
            long double delta = sqrt(m*m - y*y);
            long double cl = x - delta;
            long double cr = x + delta;
            if(cl <= cur) cur = max(cur, cr);
        }
        if(cur >= L) r = m;
        else l = m;
    }
    cout << fixed << setprecision(7) << l;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    /*
        freopen("feast.in", "r", stdin);
        freopen("feast.out", "w", stdout);
    */
    solve();
    return 0;
}

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• Subtask 21: 5 / 5