DEV Community

Abhishek Chaudhary
Abhishek Chaudhary

Posted on

Generate Random Point in a Circle

Given the radius and the position of the center of a circle, implement the function randPoint which generates a uniform random point inside the circle.

Implement the Solution class:

  • Solution(double radius, double x_center, double y_center) initializes the object with the radius of the circle radius and the position of the center (x_center, y_center).
  • randPoint() returns a random point inside the circle. A point on the circumference of the circle is considered to be in the circle. The answer is returned as an array [x, y].

Example 1:

Input
["Solution", "randPoint", "randPoint", "randPoint"]
[[1.0, 0.0, 0.0], [], [], []]
Output
[null, [-0.02493, -0.38077], [0.82314, 0.38945], [0.36572, 0.17248]]

Explanation
Solution solution = new Solution(1.0, 0.0, 0.0);
solution.randPoint(); // return [-0.02493, -0.38077]
solution.randPoint(); // return [0.82314, 0.38945]
solution.randPoint(); // return [0.36572, 0.17248]

Constraints:

  • 0 < radius <= 108
  • -107 <= x_center, y_center <= 107
  • At most 3 * 104 calls will be made to randPoint.

SOLUTION:

import random
import math

class Solution:

    def __init__(self, radius: float, x_center: float, y_center: float):
        self.r = radius
        self.cx = x_center
        self.cy = y_center

    def randPoint(self) -> List[float]:
        randRadius = self.r * math.sqrt(random.random())
        randAngle = 2 * math.pi * random.random()
        x = self.cx + randRadius * math.cos(randAngle)
        y = self.cy + randRadius * math.sin(randAngle)
        return [x, y]

# Your Solution object will be instantiated and called as such:
# obj = Solution(radius, x_center, y_center)
# param_1 = obj.randPoint()
Enter fullscreen mode Exit fullscreen mode

Top comments (0)