private void sq(List <Point> q)
{
Point p0 = hul(q);
q.Remove(p0);
Point pn = hpn(q);
q.Remove(pn);
List <Point> hup = new List <Point>()
{
p0,
pn
};
line t = new line()
{
x = p0,
y = pn
};
line dy = new line()
{
x = pn,
y = p0
};
sq(q, hup, t);
sq(q, hup, dy);
print(hup);
}
/// <summary>
/// 分治法 快包
/// </summary>
/// <param name="point">所有点</param>
/// <returns>围住</returns>
public List <Point> divide_conquer(List <Point> point)
{
Point p0 = hul_long(point); //最左边点
Point pn = hup_long(point); //最右边的点
point.Remove(p0);
point.Remove(pn);
List <Point> round_point = new List <Point>()
{
p0,
pn
};
line _line = new line()
{
x = p0,
y = pn
};
divide_conquer(point, round_point, _line);
_line = new line()
{
x = pn,
y = p0
};
divide_conquer(point, round_point, _line);
round_point = divide_conquer(round_point, true);
return(round_point);
}
private static void divide_conquer(IList <Point> point, ICollection <Point> hup, line _line)
{
if (point.Count < 1)
{
return;
}
Point[] temp = new Point[point.Count];
point.CopyTo(temp, 0);
point = temp.ToList();
Point p;
p.X = -1;
p = divide_conquer(point, _line, p);
if (p.X < 0)
{
return;
}
hup.Add(p);
line dy = new line()
{
x = _line.x,
y = p
};
divide_conquer(point, hup, dy);
dy = new line()
{
x = p,
y = _line.y
};
divide_conquer(point, hup, dy);
}
private void sq(List <Point> q, List <Point> hup, line t)
{
if (q.Count < 1)
{
return;
}
Point p;
p.X = -1;
t.n = 0;
for (int i = 0; i < q.Count; i++)
{
double n = sq(t, q[i]);
if (n > 0)
{
if (p == null || t.n < n)
{
p = q[i];
t.n = n;
}
}
else
{
q.RemoveAt(i);
i--;
}
}
if (p.X < 0)
{
return;
}
hup.Add(p);
line dy = new line()
{
x = t.x,
y = p
};
sq(q, hup, dy);
dy = new line()
{
x = p,
y = t.y
};
sq(q, hup, dy);
}
private static Point divide_conquer(IList <Point> point, line t, Point p)
{
t.n = 0;
for (int i = 0; i < point.Count; i++)
{
double n = pointline(t, point[i]);
if (n > 0)
{
if (p.X < 0 || t.n < n)
{
p = point[i];
t.n = n;
}
}
else
{
point.RemoveAt(i);
i--;
}
}
return(p);
}
private double sq(line t, Point p)
{
return(t.x.X * t.y.Y + p.X * t.x.Y + t.y.X * p.Y - p.X * t.y.Y - t.y.X * t.x.Y - t.x.X * p.Y);
}
/// <summary>
/// 点到直线
///
/// </summary>
/// <param name="t"></param>
/// <param name="p"></param>
/// <returns></returns>
private static double pointline(line t, Point p)
{
return(t.x.X * t.y.Y + p.X * t.x.Y + t.y.X * p.Y - p.X * t.y.Y - t.y.X * t.x.Y - t.x.X * p.Y);
}
