acmp 232

232.cpp

#include <vector>
#include <iostream>
#include <fstream>

using namespace std;

struct pt {
	double x, y;

	pt operator- (pt p) {
		pt res = { x - p.x, y - p.y };
		return res;
	}
};

struct circle : public pt {
	double r;
	circle() {
		x = 0;
		y = 0;
		r = 0;
	}

	circle(double _x, double _y, double _r) {
		x = _x;
		y = _y;
		r = _r;
	}
};

struct line {
	double a, b, c;
};

const double EPS = 1E-9;

double sqr(double a) {
	return a * a;
}


void tangents(pt c, double r1, double r2, vector<line> & ans) {
	double r = r2 - r1;
	double z = sqr(c.x) + sqr(c.y);
	double d = z - sqr(r);
	if (d < -EPS)  return;
	d = sqrt(abs(d));
	line l;
	l.a = (c.x * r + c.y * d) / z;
	l.b = (c.y * r - c.x * d) / z;
	l.c = r1;
	ans.push_back(l);
}

vector<line> tangents(circle a, circle b) {
	vector<line> ans;
	for (int i = -1; i <= 1; i += 2)
		for (int j = -1; j <= 1; j += 2)
			tangents(b - a, a.r*i, b.r*j, ans);
	for (size_t i = 0; i<ans.size(); ++i)
		ans[i].c -= ans[i].a * a.x + ans[i].b * a.y;
	return ans;
}

#define DEBUG

int main() {
	int numberOfPoints;
	ifstream fileInput("input.txt");
#ifdef DEBUG
	cout << fileInput.is_open() << endl;
#endif
	fileInput >> numberOfPoints;
	vector<circle> trees(numberOfPoints);
	double x = 0, 
		   y = 0,
		   r = 0;

	for (size_t i = 0; i < numberOfPoints; ++i) {
		fileInput >> x >> y >> r;
		trees[i] = circle(x, y, r);
	}
	

#ifdef DEBUG
	for (size_t i = 0; i < numberOfPoints; ++i) {
		cout << trees[i].x << " " << trees[i].y << " " << trees[i].r << endl;
	}
#endif
	 
	for (size_t i = 0; i < numberOfPoints; ++i) {
		for (size_t j = 0; j < numberOfPoints; ++j) {
			vector<line>  tang = tangents(trees[i], trees[j]);
			for (size_t k = 0; k < numberOfPoints; ++k) {

			}
		}
	}


	return 0;
}