GenerateRandomPointinaCircle.java

class Solution {

    double a;
    double b;
    double r;

    Random rand = null;

    public Solution(double radius, double x_center, double y_center) {
        this.a= x_center;
        this.b= y_center;
        this.r = radius;
        rand = new Random();

    }

    public double[] randPoint() {

        double x = getRandomCoordinate(r, a);

        double y = getRandomCoordinate(r, b);

        while(getDistance(x,y) >= r*r){
            x = getRandomCoordinate(r, a);
            y = getRandomCoordinate(r, b);
        }

        return new double[]{x,y};

    }

    private double getDistance(double x, double y){
        return (x-a)*(x-a) + (y-b)*(y-b);
    }

    private double getRandomCoordinate(double r, double c){
        return c - r + Math.random()*(2*r);
        // a -r + radom(2r);
    }
}

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