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Generate Random Point in a Circle

Given the radius and x-y positions of the center of a circle, write a function randPoint which generates a uniform random point in the circle. Note:

  1. input and output values are in floating-point.

  2. radius and x-y position of the center of the circle is passed into the class constructor.

  3. a point on the circumference of the circle is considered to be in the circle.

  4. randPoint returns a size 2 array containing x-position and y-position of the random point, in that order.



Example 1:



Input:  ["Solution","randPoint","randPoint","randPoint"] [[1,0,0],[],[],[]]
Output: [null,[-0.72939,-0.65505],[-0.78502,-0.28626],[-0.83119,-0.19803]]


Example 2:


Input:  ["Solution","randPoint","randPoint","randPoint"] [[10,5,-7.5],[],[],[]]
Output: [null,[11.52438,-8.33273],[2.46992,-16.21705],[11.13430,-12.42337]]


Explanation of Input Syntax:

The input is two lists: the subroutines called and their arguments. Solution's constructor has three arguments, the radius, x-position of the center, and y-position of the center of the circle. randPoint has no arguments. Arguments are always wrapped with a list, even if there aren't any.


Solution:



class Solution {
    double r;
    double x;
    double y;

    public Solution(double radius, double x_center, double y_center) {
        this.r=radius;
        this.x=x_center;
        this.y=y_center;
    }
    
    public double[] randPoint() {
        double minx = x-r;
        double maxx = x+r;
        double miny = y-r;
        double maxy = y+r;
        
        double[] result = new double[2];
        result[0] = ((Math.random()*(maxx-minx))+minx);
        result[1] = ((Math.random()*(maxy-miny))+miny);
        
        while((result[0]-x)*(result[0]-x) + (result[1]-y)*(result[1]-y)>=r*r)
        {
            result[0] = ((Math.random()*(maxx-minx))+minx);
            result[1] = ((Math.random()*(maxy-miny))+miny);
        }
        
        return result;
    }
    
}

/**
 * Your Solution object will be instantiated and called as such:
 * Solution obj = new Solution(radius, x_center, y_center);
 * double[] param_1 = obj.randPoint();
 */



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