## Algoritmo de Angle.

Cualquier duda no dudes en contactar.

``````/**
* Author: Simon Lindholm
* Date: 2015-01-31
* Source:
* Description: A class for ordering angles (as represented by int points and
*  a number of rotations around the origin). Useful for rotational sweeping.
*  Sometimes also represents points or vectors.
* Usage:
*  vector<Angle> v = {w[0], w[0].t360() ...}; // sorted
*  int j = 0; FOR(i,0,n) { while (v[j] < v[i].t180()) ++j; }
*  // sweeps j such that (j-i) represents the number of positively oriented triangles with vertices at 0 and i
* Status: Used, works well
*/
#pragma once

struct Angle {
int x, y;
int t;
Angle(int x, int y, int t=0) : x(x), y(y), t(t) {}
Angle operator-(Angle b) const { return {x-b.x, y-b.y, t}; }
assert(x || y);
if (y < 0) return (x >= 0) + 2;
if (y > 0) return (x <= 0);
return (x <= 0) * 2;
}
Angle t90() const { return {-y, x, t + (quad() == 3)}; }
Angle t180() const { return {-x, -y, t + (quad() >= 2)}; }
Angle t360() const { return {x, y, t + 1}; }
};
bool operator<(Angle a, Angle b) {
// add a.dist2() and b.dist2() to also compare distances
return make_tuple(a.t, a.quad(), a.y * (ll)b.x) <
}

// Given two points, this calculates the smallest angle between
// them, i.e., the angle that covers the defined line segment.
pair<Angle, Angle> segmentAngles(Angle a, Angle b) {
if (b < a) swap(a, b);
return (b < a.t180() ?
make_pair(a, b) : make_pair(b, a.t360()));
}
Angle operator+(Angle a, Angle b) { // point a + vector b
Angle r(a.x + b.x, a.y + b.y, a.t);
if (a.t180() < r) r.t--;
return r.t180() < a ? r.t360() : r;
}
Angle angleDiff(Angle a, Angle b) { // angle b - angle a
int tu = b.t - a.t; a.t = b.t;
return {a.x*b.x + a.y*b.y, a.x*b.y - a.y*b.x, tu - (b < a)};
}
``````