Submission #83839

#	Time	Username	Problem	Language	Result	Execution time	Memory
83839		aminra	The Forest of Fangorn (CEOI14_fangorn)	C++14	100 / 100	1755 ms	1000 KiB

fangorn

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double ld;
const int MAXN = (int)1e5 + 7;
const int infint = (int)1e9;
const int MOD = (int)1e9 + 9;
const ll inf = (ll)2e18 + 2;
struct point{
	ll x, y;
	point operator - (const point &other) const
    {
        return {x - other.x, y - other.y};
    }
};
vector<point> terminal;
bool cross(point a, point b)
{
	return 1LL * a.x * b.y > 1LL * a.y * b.x;
}
bool check(point a)
{
	return a.x > 0 || (a.x == 0 && a.y > 0);
}
bool cmp(point a, point b)
{
	//clockwise correct.
	if(check(a) != check(b))
		return check(a);
	return cross(a, b);
}
int get_first(point P)
{
	int L = 0, R = terminal.size() - 1;
	while(L <= R)
	{
		int mid = (L + R) >> 1;
		if(cmp(P, terminal[mid]))
			R = mid - 1;
		else
			L = mid + 1;
	}
	return L % terminal.size();
}
ll w, h, m, n, can[MAXN];
point S, T[MAXN], C[MAXN];
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin >> w >> h >> S.x >> S.y;
	cin >> m;
	for (int i = 0; i < m; i++)
	{
		cin >> C[i].x >> C[i].y;
		can[i] = 1;
	}
	cin >> n;
	for (int i = 0; i < n; i++)
		cin >> T[i].x >> T[i].y;
	for (int i = 0; i < n; i++)
	{
		terminal.clear();
		for (int j = 0; j < n; j++)
			if(j != i)
				terminal.push_back(T[i] - T[j]);
		sort(terminal.begin(), terminal.end(), cmp);
		
		int saboon = get_first(S - T[i]);
		for (int j = 0; j < m; j++)
			if(get_first(C[j] - T[i]) != saboon)
				can[j] = 0;
	}
	vector<int> ans;
	for (int i = 0; i < m; i++)
		if(can[i])
			ans.push_back(i);
	cout << ans.size() << "\n";
	for (auto u : ans)
		cout << u + 1 << " ";
}

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 20 / 20