Find K Closest Points to the Origin

Given a list of points on the 2-D plane and an integer K. The task is to find K closest points to the origin and print them.

Note: The distance between two points on a plane is the Euclidean distance.


Input : point = [[3, 3], [5, -1], [-2, 4]], K = 2
Output : [[3, 3], [-2, 4]]

Input : point = [[1, 3], [-2, 2]], K  = 1
Output : [[-2, 2]]

Approach :

  • Sort the points by distance using Euclidean distance formula.
  • Select first K points form the list
  • Print the points obtained in any order.

Consider two points with coordinates as (x1, y1) and (x2, y2) respectively. The euclidean distance between these two points will be:

√{(x2-x1)2 + (y2-y1)2}

Below is the implementation of the above approach:





# Python program for implementation of 
# above approach
# Function to return required answer
def pClosest(points, K):
    points.sort(key = lambda K: K[0]**2 + K[1]**2)
    return points[:K]
# Driver program
points = [[3, 3], [5, -1], [-2, 4]]
K = 2
print(pClosest(points, K))



[[3, 3], [-2, 4]]

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