type Solution struct {
	r float64
	x float64
	y float64
}

func Constructor(radius float64, x_center float64, y_center float64) Solution {
	return Solution{
		r: radius,
		x: x_center,
		y: y_center,
	}
}

func (this *Solution) RandPoint() []float64 {
	phi := rand.Float64() * 2.0 * math.Pi
	radius := math.Sqrt(rand.Float64()) * this.r // !!!
	dx, dy := radius*math.Cos(phi), radius*math.Sin(phi)
	return []float64{this.x + dx, this.y + dy}
}

/**
 * Your Solution object will be instantiated and called as such:
 * obj := Constructor(radius, x_center, y_center);
 * param_1 := obj.RandPoint();
 */