#include <iostream>
#include <vector>
#include <iomanip>
using namespace std;
using i64 = long long;
using f64 = double;
f64 dist(f64 a, f64 b, f64 c, f64 d) {
return sqrt((c - a) * (c - a) + (d - b) * (d - b));
}
int main(void) {
i64 N_tmp, L; cin >> N_tmp >> L;
vector<pair<i64, i64> > towers;
for (int i = 0; i < N_tmp; i++) {
pair<i64, i64> p;
cin >> p.first >> p.second;
// printf("p: %lld, %lld\n", p.first, p.second);
if (i == 0 || towers.back().first != p.first) {
towers.push_back(p);
} else {
towers.pop_back();
}
}
f64 max_dist = 0;
i64 N = towers.size();
for (int i = 0, j = 1; i < N - 1 && j < N; i++, j++) {
f64 P1_x = towers[i].first;
f64 P1_y = towers[i].second;
f64 P2_x = towers[j].first;
f64 P2_y = towers[j].second;
f64 x = (P2_x * P2_x - P1_x * P1_x + P2_y * P2_y - P1_y * P1_y) / (2 * (P2_x - P1_x));
max_dist = max(max_dist, dist(P1_x, P1_y, x, 0));
}
// then try two endpoints
max_dist = max(max_dist, dist(towers[0].first, towers[0].second, 0, 0));
if (L >= towers[N - 1].first) {
max_dist = max(max_dist, dist(towers[N - 1].first, towers[N - 1].second, 0, N));
}
cout << setprecision(10);
cout << max_dist << endl;
}
Compilation message
mobile.cpp: In function 'f64 dist(f64, f64, f64, f64)':
mobile.cpp:11:12: error: 'sqrt' was not declared in this scope
11 | return sqrt((c - a) * (c - a) + (d - b) * (d - b));
| ^~~~
