[leetcode]973. K Closest Points to Origin 离原点距离最近的K个点

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.)

题意
求离原点距离最近的K个点

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思路

维护一个minHeap

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代码

class Solution {
    public int[][] kClosest(int[][] points, int K) {
           int[][] res = new int[K][2];

        PriorityQueue<int[]> minHeap = new PriorityQueue<>((a, b) -> (a[0] * a[0] + a[1] * a[1]) - (b[0] * b[0] + b[1] * b[1]));   
        for (int[] point : points) {
            minHeap.add(point);
        }
        
        for (int i = 0; i < K; i++) {
            res[i] = minHeap.poll();
        }
        return res;

    }
}