動機

sort與heap差在一個能插入，另一個不能

Problem

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).

 

Example 1:

Input: points = [[1,3],[-2,2]], k = 1Output: [[-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 = 2Output: [[3,3],[-2,4]]Explanation: The answer [[-2,4],[3,3]] would also be accepted.

 

Constraints:

  • 1 <= k <= points.length <= 104
  • -104 < xi, yi < 104

Sol

class Solution:
    def kClosest(self, ps: List[List[int]], k: int) -> List[List[int]]:
        ps.sort(key=lambda p: p[0]**2+p[1]**2)
        return ps[:k]