Problem:
Parallel/Orthogonal

For given two lines s1 and s2, print "2" if they are parallel, "1" if they are orthogonal, or "0" otherwise.

s1 crosses points p0 and p1, and
s2 crosses points p2 and p3.

Input

The entire input looks like:

q (the number of queries)
1st query
2nd query
...
qth query

Each query consists of integer coordinates of the points p0, p1, p2, p3 in the following format:

xp0 yp0 xp1 yp1 xp2 yp2 xp3 yp3

Output

For each query, print "2", "1" or "0".

Constraints

1 ≤ q ≤ 1000

-10000 ≤ xpi, ypi ≤ 10000

p0 ≠ p1 and
p2 ≠ p3.

Sample Input 1

3
0 0 3 0 0 2 3 2
0 0 3 0 1 1 1 4
0 0 3 0 1 1 2 2

Sample Output 1

2
1
0

Solution in Python3 (judge verdict: Accepted)

from math import sin, cos, atan2

def sgn(x, eps=1e-10):
    if x < -eps: return -1
    if -eps <= x <= eps: return 0
    if eps < x: return 1

class Vector():
    def __init__(self, x=0.0, y=0.0):
        self.x = x
        self.y = y

    def arg(self):
        return atan2(self.y, self.x)

    def norm(self):
        return (self.x**2 + self.y**2)**0.5

    def rotate(self, t):
        nx = self.x * cos(t) - self.y * sin(t)
        ny = self.x * sin(t) + self.y * cos(t)
        return Vector(nx, ny)

    def counter(self):
        nx = -self.x
        ny = -self.y
        return Vector(nx, ny)

    def times(self, k):
        nx = self.x * k
        ny = self.y * k
        return Vector(nx, ny)

    def unit(self):
        norm = self.norm()
        nx = self.x / norm
        ny = self.y / norm
        return Vector(nx, ny)

    def normal(self):
        norm = self.norm()
        nx = -self.y / norm
        ny = self.x / norm
        return Vector(nx, ny)

    def add(self, other): #Vector, Vector -> Vector
        nx = self.x + other.x
        ny = self.y + other.y
        return Vector(nx, ny)

    def sub(self, other):
        nx = self.x - other.x
        ny = self.y - other.y
        return Vector(nx, ny)

    def dot(self, other): #Vector, Vector -> int
        return self.x * other.x + self.y * other.y

    def cross(self, other): #Vector, Vector -> int
        return self.x * other.y - self.y * other.x

    def __str__(self):
        return '{:.9f}'.format(self.x) + ' ' + '{:.9f}'.format(self.y)

class Line():
    def __init__(self, bgn=Vector(), end=Vector()):
        self.bgn = bgn
        self.end = end

    def build(self, a, b, c): #ax + by == 1
        assert sgn(a) != 0 or sgn(b) != 0
        if sgn(b) == 0:
            self.bgn = Vector(-c / a, 0.0)
            self.end = Vector(-c / a, 1.0)
        else:
            self.v = Vector(0, -c / b)
            self.u = Vector(1.0, -(a + b) / b)

    def vec(self):
        return self.end.sub(self.bgn)

    def projection(self, point):
        v = self.vec()
        u = point.sub(self.bgn)
        k = v.dot(u) / v.norm()
        h = v.unit().times(k)
        return self.bgn.add(h)

    def refrection(self, point):
        proj = self.projection(point)
        return proj.sub(point).times(2).add(point)

    def is_orthogonal(self, other):
        v = self.vec()
        u = other.vec()
        if sgn(v.dot(u)) == 0:
            return True
        else:
            return False

    def is_parallel(self, other):
        v = self.vec()
        u = other.vec()
        if sgn(v.cross(u)) == 0:
            return True
        else:
            return False

q = int(input())
for _ in range(q):
    xp0, yp0, xp1, yp1, xp2, yp2, xp3, yp3 = map(int, input().split())
    p0 = Vector(xp0, yp0)
    p1 = Vector(xp1, yp1)
    p2 = Vector(xp2, yp2)
    p3 = Vector(xp3, yp3)
    s1 = Line(p0, p1)
    s2 = Line(p2, p3)
    if s1.is_parallel(s2):
        print(2)
    elif s1.is_orthogonal(s2):
        print(1)
    else:
        print(0)