Gets the n closest points to a target point.

n_closest_points.py

from typing import List, Tuple
from math import sqrt
from collections import defaultdict
from itertools import chain

def n_closest_points(n: int, target: Tuple[int, int], points: List[Tuple[int, int]]) -> int:
  
  lengths = defaultdict(list)
  
  for point in points:
    lengths[sqrt((target[0] - point[0])**2 + (target[1] - point[1])**2)].append(point)
  
  closest = chain.from_iterable(lengths[key] for key in sorted(lengths.keys()))
    
  return list(closest)[:n]