Submission #24974571

---

Source Code Expand

#include "bits/stdc++.h"

#define int long long

using namespace std;
using ll = long long;
using P = pair<ll, ll>;
const ll INF = (1LL << 61);
ll mod = 1000000007;
using ld = long double;
ld EPS = 1e-8;
ld PI = 3.14159265358979;

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int N; cin >> N;
	vector<ld>X(N), Y(N);
	for (int i = 0; i < N; i++)cin >> X[i] >> Y[i];
	ld ans = 0;
	for (int i = 0; i < N; i++) {
		vector<pair<ld, ld>>p;
		for (int j = 0; j < N; j++) {
			p.push_back({X[j] - X[i], Y[j] - Y[i]});
		}
		vector<pair<ld, int>>now;
		for (int j = 0; j < N; j++) {
			ld t = atan2l(p[j].second, p[j].first);
			t *= 180.0; t /= PI;
			if (t + EPS < 0)t += 360.0;
			now.push_back({ t, j });
		}
		sort(now.begin(), now.end());
		for (int j = 0; j < N; j++) {
			if (i == now[j].second)continue;
			ld tmp = now[j].first + 180.0;
			if (tmp - EPS > 360.0)tmp -= 360.0;
			pair<ld, int>tmp2 = { tmp, -INF };
			int idx = lower_bound(now.begin(), now.end(), tmp2) - now.begin();
			for (int k = idx - 2; k <= idx + 2; k++) {
				int a = k;
				if (a < 0)a += N;
				if (a >= N)a %= N;
				if (now[a].second == i || now[a].second == now[j].second)continue;
				ans = max(ans, min(abs(now[j].first - now[a].first), 360.0 - abs(now[j].first - now[a].first)));

			}
		}
	}
	cout << fixed << setprecision(15) << ans << endl;
	return 0;


}

Submission Info

Judge Result