[UVA] Amphiphilic Carbon Molecules

题目:https://vjudge.net/problem/UVA-1606

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#pragma warning(disable:4996)
using namespace std;
const int maxn = 1000 + 5;
int n;
struct Point {
	int x, y,color;
	double angle;
	bool operator < (const Point& rhs) const
	{
		return angle < rhs.angle;
	}
	void input()
	{
		cin >> x >> y >> color;
	}
};

Point s[maxn],v[maxn];
bool det(const Point a, const Point b)
{
	return a.x*b.y - a.y*b.x >= 0;
}

int solve()
{
	if (n <= 2) return 2;
	int ans = 0;
	for (int i = 0; i < n; i++)
	{
		int k = 0;
		for (int j = 0; j < n; j++)
		{
			if (j != i)
			{
				v[k].x = s[j].x - s[i].x;
				v[k].y = s[j].y - s[i].y;
				if (s[j].color)
				{
					v[k].x = -v[k].x;
					v[k].y = -v[k].y;
				}
				v[k].angle = atan2(v[k].y, v[k].x);
				k++;
			}
			
		}

		sort(v, v + k);
		int L = 0, R = 0, cnt = 2;
		while (L < k) {
			if (R == L) { R = (R + 1) % k; cnt = 2; } 
			while (R != L && det(v[L], v[R])) { R = (R + 1) % k; cnt++; } 
			ans = max(ans, cnt);
			cnt--;
			L++;
		}
	}
	return ans;
}
int main()
{

	while (cin >> n &&n)
	{
		for (int i = 0; i < n; i++)
			scanf("%d%d%d", &s[i].x, &s[i].y, &s[i].color);

		cout << solve() << endl;
	}

	return 0;
}

 

你可能感兴趣的:(C++)