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.)
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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.)
Java Solution:
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class Solution {
class point{
point(int x,int y){
this.x = x;
this.y = y;
}
int x;
int y;
}
class pointId{
pointId(point mid, int mDis){
id = mid;
distance = mDis;
}
point id;
int distance;
}
private Comparator<pointId> mComparator = new Comparator<pointId>(){
@Override
public int compare(pointId t1, pointId t2) {
return t1.distance - t2.distance;
}
};
public int[][] kClosest(int[][] points, int K) {
int len = points.length;
Queue<pointId> mQueue = new PriorityQueue<>(K, mComparator);
for (int []ele:points) {
int distance = EuclideanDistance(ele[0],ele[1],0,0);
pointId mId = new pointId(new point(ele[0],ele[1]), distance);
mQueue.add(mId);
}
int [][] closest = new int[K][2];
int i = 0;
while(i < K){
pointId tmp = mQueue.poll();
closest[i][0] = tmp.id.x;
closest[i][1] = tmp.id.y;
i++;
}
return closest;
}
private static int EuclideanDistance(int X, int Y, int oX, int oY){
int tmp = (X - oX) * (X - oX) + (Y - oY) * (Y - oY);
return tmp;
}
}
