973. K Closest Points to Origin

package Sort;

import java.util.Arrays;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.List;

public class KClosest_973 {
	// 973. K Closest Points to Origin
/*	We have a list of points on the plane.  Find the K closest points to the origin (0, 0).

	(Here, the distance between two points on a plane is the Euclidean distance.)

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

	 

	Example 1:

	Input: points = [[1,3],[-2,2]], K = 1
	Output: [[-2,2]]
	Explanation: 
	The distance between (1, 3) and the origin is sqrt(10).
	The distance between (-2, 2) and the origin is sqrt(8).
	Since sqrt(8) < sqrt(10), (-2, 2) is closer to the origin.
	We only want the closest K = 1 points from the origin, so the answer is just [[-2,2]].

	Example 2:

	Input: points = [[3,3],[5,-1],[-2,4]], K = 2
	Output: [[3,3],[-2,4]]
	(The answer [[-2,4],[3,3]] would also be accepted.)

	 

	Note:

	    1 <= K <= points.length <= 10000
	    -10000 < points[i][0] < 10000
	    -10000 < points[i][1] < 10000

	來源：力扣（LeetCode）
	鏈接：https://leetcode-cn.com/problems/k-closest-points-to-origin
	著作權歸領釦網絡所有。商業轉載請聯繫官方授權，非商業轉載請註明出處。*/
	public int[][] kClosest(int[][] points, int K) {
		Arrays.sort(points, new Comparator<int[]>() {

			@Override
			public int compare(int[] a, int[] b) {
				return (a[0]*a[0]+a[1]*a[1])-(b[0]*b[0]+b[1]*b[1]);
			}
		});
		int[][] res=new int[K][2];
		for(int i=0;i<K;i++) {
			res[i]=points[i];
		}
		
		return res;

	}

}