Submission #203188

#	Time	Username	Problem	Language	Result	Execution time	Memory
203188		Neklixx	Balloons (CEOI11_bal)	C++14	100 / 100	1389 ms	12340 KiB

bal

#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define all(v) v.begin(), v.end()
#define sh cin.tie(0); cin.sync_with_stdio(0); cout.tie(0);
#define FILE freopen("test.in", "r", stdin);
#define vprint(v) for (int ii = 0; ii < v.size(); ii++){cout << v[ii] << " ";}
#define debugv(v) if (v.size() != 0) {cout << "[ "; for (int __ = 0; __ < (int)(v.size()) - 1; __++){cout << v[__] << ", ";} cout << v[(int)(v.size()) - 1] << " ]" << endl;} else {cout << "[]" << endl;}
#define debug cout << "-----------------------------------------------" << endl;
#define print1(a) cout << "{ " << a << " }" << endl;
#define print2(a, b) cout << "{ " << a << ", " << b << " }" << endl;
#define print3(a, b, c) cout << "{ " << a << ", " << b << ", " << c << " }" << endl;
#define print4(a, b, c, d) cout << "{ " << a << ", " << b << ", " << c << ", " << d << " }" << endl;
using namespace std;
#define int long long
#define double long double
const double INF = 1e11 + 228;
const int MAXN = 2e5 + 228;
double ans[MAXN];
const double eps = 1e-13;
const double eps2 = 0;
double intersect1(double x1, double x2, double t1, double t2) {
	//print4(x1, x2, t1, (((x2 / (2 * t2)) - (x1 / (2 * t1))) * 2 * t1 * t2) / (t1 - t2));
	return ((((x2 / (2 * t2)) - (x1 / (2 * t1))) * 2 * t1 * t2) / (t1 - t2));
} 

double get(pair<double, double> to, double h) {
	//double xx = (to.S / (4 * to.F)) * to.S - ((2.0 * to.S) / (4 * to.F)) * h + ((h / (4 * to.F)) * h);
	return ((to.S - h) * (to.S - h)) / (4 * to.F);// + (h * h) / (4 * to.F) - (2 * h * to.S) / (4 * to.F);
}

double sqr(double x) {
	double l = 0, r = 1e9 + 1;
	while (r - l > eps) {
		double mid = (l + r) / 2;
		if (mid * mid > x) {
			r = mid;
		} else {
			l = mid;
		}
	}
	return l;
}

signed main()
{
#ifdef LOCAL
    FILE;
#endif
    sh;
	int n;
	cin >> n;
	vector<pair<int, int>> v;
	for (int i = 0; i < n; i++) {
		int aa, bb;
		cin >> aa >> bb;
		v.pb({aa, bb});
	}    

	vector<pair<double, double>> s;
	vector<double> x1;
	for (int i = 0; i < n; i++) {
		double now = v[i].S;
		//print1(i);
		while (x1.size() > 0 && x1.back() <= (double)v[i].F) {
			x1.pop_back();
			s.pop_back();
		}
		int id = x1.size();//upper_bound(all(x1), (double)v[i].F) - x1.begin();
		//print2(i, id);
		/*for (auto oo : s) {
			cout << oo.S << ' ';
		}
		cout << endl;*/
		if (s.size() > 0) {
			assert((int)(s.size()) - id - 1 >= 0);
			//print4("t", s.size(), id, x1.size());
			pair<double, double> to = s[id];
			double cl = get(to, v[i].F);
			now = min(now, cl);
		}
		while (s.size() > 0 && s.back().F <= now) {
			s.pop_back();
		}
		while (x1.size() + 1 > s.size() && s.size() != 0) {
			x1.pop_back();
		}
		if (s.size() == 0) {
			x1.clear();
		}
		while (s.size() >= 2 && get(s.back(), intersect1(s.back().S, (double)v[i].F, sqr(s.back().F), sqr(now))) >= get(s[s.size() - 2], intersect1(s.back().S, (double)v[i].F, sqr(s.back().F), sqr(now))) /*intersect1(s[s.size() - 2].S, s.back().S, sqr(s[s.size() - 2].F), sqr(s.back().F))*/) {
			s.pop_back();
			x1.pop_back();
		}
		ans[i] = now;
		//print1(now);
		if (s.size() > 0) {
			x1.pb(intersect1(s.back().S, (double)v[i].F, sqr(s.back().F), sqr(now)));
		}
		//print1("ok");
		s.pb({now, (double)v[i].F});
	}

	for (int i = 0; i < n; i++) {
		cout << fixed << setprecision(5) << ans[i] << '\n';
	}
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10