K Closest Points to Origin.md

Given an array of points where points[i] = [xi, yi] 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 (i.e., √(x1 - x2)2 + (y1 - y2)2).

You may return the answer in any order. The answer is guaranteed to be unique (except for the order that it is in).

Simplest O(nlogn) answer, we sort the array, and then use slice to pick the nearst

/*
Input: points = [[3,3],[5,-1],[-2,4]], k = 2
Output: [[3,3],[-2,4]]

After the formular is [18 26 20], sort the order to become [18, 20, 26]
Accordingly, it becomes [[3,3],[-2,4],[5,-1]], pick the first two, the answer is [[3,3],[-2,4]]
*/
var kClosest = function(points, K) {
    points.sort((a,b) => (a[0]*a[0] + a[1]*a[1]) - (b[0]*b[0] + b[1]*b[1]))

    return points.slice(0,K)
};