K Closest Points to Origin
Given an array of points where points[i] = [x, y] represents a point on the X-Y plane and an integer k, return the k closest points to the origin (0, 0).
The distance between two points on the X-Y plane is the Euclidean distance (\sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}).
You may return the answer in any order. The answer is guaranteed to be unique (except for the order).
kClosest([[1, 3], [-2, 2]], 1); // [[-2, 2]]
// Distance of (1, 3) is sqrt(10), distance of (-2, 2) is sqrt(8)
// (-2, 2) is closer to origin.