geometric_helpers.hh

// Common geometric helpers to use in different algorithms.
// Auxiliary type definitions.
#ifndef GEOMETRIC_HELPERS_HH
#define GEOMETRIC_HELPERS_HH

#include <stdio.h>
#include <vector>
#include <iostream>

typedef long long int LL;

// Macro for calculating cross product.
#define Det(a, b, c) (LL(b.x - a.x) * LL(c.y - a.y) \
		- LL(b.y - a.y) * LL(c.x - a.x))

#define DetPointer(a, b, c) (LL(b->x - a->x) * LL(c->y - a->y) \
		- LL(b->y - a->y) * LL(c->x - a->x))

#define abs_int(x) ((x) > 0 ? x : -x)

// Struct representing point with integer coordinates.
struct POINT {
	int x, y;

	POINT(int x = 0, int y = 0) : x(x), y(y) { }

	bool operator ==(const POINT& a) {
		return a.x == x && a.y == y;
	}

	void print() const {
		std::cout << x << " " << y << "\n";
	}
};

typedef std::vector<POINT*> POINTS;

// Function designating order with regards to coordinates of
// pointers to points set.
bool OrderXY(const POINT* a, const POINT* b) {
	return a->x == b->x ? a->y < b->y : a->x < b->x;
}

#endif // GEOMETRIC_HELPERS_HH