K Closest Points to Origin

Question

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]].

LeetCodeleetcode.com/problems/k-closest-points-to-origin

Solution

/*
@priorityQueue to add smallest distance, if size > k, poll the larger one.
*/
public int[][] kClosest(int[][] points, int K) {
    Queue<int[]> maxHeap = new PriorityQueue<>( (a,b) -> b[2] - a[2]);
    
    for (int[] point : points) {
        int[] distance = new int[3];
        distance[0] = point[0];
        distance[1] = point[1];
        distance[2] = point[0] * point[0] + point[1] * point[1];
        if (maxHeap.size() == K) {
            if (distance[2] < maxHeap.peek()[2]) {
                int[] pollDistance = maxHeap.poll();
                maxHeap.offer(distance);
            }
        }else {
            maxHeap.offer(distance);               
        }
    }
    int[][] temp = new int[K][2];
    int index = 0;
    for (int[] result : maxHeap) {
        temp[index][0] = result[0];
        temp[index++][1] = result[1];            
    }
    return temp;
}