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MAY-30 2020 Challenge

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. 1 <= K <= points.length <= 10000
  2. -10000 < points[i][0] < 10000
  3. -10000 < points[i][1] < 10000


Solution in Java:


class Solution {
    public int[][] kClosest(int[][] points, int K) {
 PriorityQueue<int[]> maxHeap = new PriorityQueue<>(Comparator.comparing(a -> -a[0] * a[0] - a[1] * a[1]));        
        for(int[] point : points){
            maxHeap.add(point);
            if(maxHeap.size() > K)
                maxHeap.remove();
        }
        
        int[][] result = new int[K][2];
       
        while(K-- > 0){
            result[K] = maxHeap.poll();
        }
        
        return result;
    }
}

K Closest Points to Origin

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