In this Leetcode Generate Random Point in a Circle problem solution 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].
Problem solution in Python.
class Solution(object):
def __init__(self, radius, x_center, y_center):
"""
:type radius: float
:type x_center: float
:type y_center: float
"""
self.radius = radius
self.x_center = x_center
self.y_center = y_center
def randPoint(self):
"""
:rtype: List[float]
"""
theta = 2*math.pi*random.random()
r = self.radius * math.sqrt(random.random())
x = self.x_center + r * math.cos(theta)
y = self.y_center + r * math.sin(theta)
return [x, y]
Problem solution in Java.
public class Solution {
double radius;
double xCentre;
double yCentre;
public Solution(double radius, double x_center, double y_center) {
this.radius = radius;
this.xCentre = x_center;
this.yCentre = y_center;
}
public double[] randPoint() {
double randomRadius = Math.sqrt(Math.random()) * radius;
double angle = Math.random() * 2 * Math.PI;
double x = xCentre + randomRadius * Math.cos(angle);
double y = yCentre + randomRadius * Math.sin(angle);
return new double[]{x, y};
}
}
Problem solution in C++.
class Solution {
public:
double r;
double x;
double y;
Solution(double radius, double x_center, double y_center) {
r = radius;
x = x_center;
y = y_center;
}
vector<double> randPoint() {
double x_, y_;
do{
double rand_double_x = (double)rand() / RAND_MAX; // Gets random double between [0,1]
double rand_double_y = (double)rand() / RAND_MAX;
x_ = (2*(rand_double_x) - 1.0) * r; //To get [-1, 1]
y_ = (2*(rand_double_y) - 1.0) * r; //To get [-1, 1]
} while(x_*x_ + y_*y_ > r*r);
return {x+x_, y+y_};
}
};
