973. 最接近原点的 K 个点

class Solution(object):
    def kClosest(self, points, K):
        """
        :type points: List[List[int]]
        :type K: int
        :rtype: List[List[int]]
        """
        res = []
        for item in points:
            a = lambda x: x[0]**2 + x[1]**2
            points.sort(key=a)
            return points[:K]