Class 2 - Find the Torsional Angle HackerRank Solution In Python

Problem

You are given four points A, B, C and D in a 3-dimensional Cartesian coordinate system. You are required to print the angle between the plane made by the points A, B, C and B, C, D in degrees(not radians). Let the angle be PHI.

Cos(PHI) = (X.Y)/|X||Y| where X = AB x BC and Y = BC x CD.

Here, X.Y means the dot product of X and Y, and AB x BC means the cross product of vectors AB and BC. Also, AB = B – A.

Input Format

One line of input containing the space separated floating number values of the X, Y and Z coordinates of a point.

Output Format

Output the angle correct up to two decimal places.

Sample Input

0 4 51 7 60 5 91 7 2

Sample Output

8.19

Solution – Class 2 – Find the Torsional Angle | HackerRank

import mathclass Points(object):    def __init__(self, x, y, z):        self.x=x        self.y=y        self.z=z    def __sub__(self, no):        return  Points((self.x-no.x),(self.y-no.y),(self.z-no.z))    def dot(self, no):        return (self.x*no.x)+(self.y*no.y)+(self.z*no.z)    def cross(self, no):        return Points((self.y*no.z-self.z*no.y),(self.z*no.x-self.x*no.z),(self.x*no.y-self.y*no.x))            def absolute(self):        return pow((self.x ** 2 + self.y ** 2 + self.z ** 2), 0.5)if __name__ == '__main__':    points = list()    for i in range(4):        a = list(map(float, input().split()))        points.append(a)    a, b, c, d = Points(*points[0]), Points(*points[1]), Points(*points[2]), Points(*points[3])    x = (b - a).cross(c - b)    y = (c - b).cross(d - c)    angle = math.acos(x.dot(y) / (x.absolute() * y.absolute()))    print("%.2f" % math.degrees(angle))

NOTE: The problem solved above, Class 2 – Find the Torsional Angle, was generated by HackerRank and the solution was brought by the admin of  CodingSolutions for educational purpose. Got any issues with the code? Ask your questions in the comment box and I shall attend to it.