973. K Closest Points to Origin #

题目 #

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

题目大意 #

找出 K 个距离坐标原点最近的坐标点。

解题思路 #

这题也是排序题，先将所有点距离坐标原点的距离都算出来，然后从小到大排序。取前 K 个即可。

代码 #

package leetcode

import "sort"

// KClosest define
func KClosest(points [][]int, K int) [][]int {
	sort.Slice(points, func(i, j int) bool {
		return points[i][0]*points[i][0]+points[i][1]*points[i][1] <
			points[j][0]*points[j][0]+points[j][1]*points[j][1]
	})
	ans := make([][]int, K)
	for i := 0; i < K; i++ {
		ans[i] = points[i]
	}
	return ans
}