149. Max Points on a Line

Given n points on a 2D plane, find the maximum number of points that lie on the same straight line.

这个题目难不是很难，建立一个dict,斜率：该斜率上点的个数，算斜率特别要注意，如果使用Fraction(3,4)，则会非常影响性能，使用np.longdouble(1)满足要求，真是坑爹。

from fractions import Fraction
from collections import defaultdict
import numpy as np
d = defaultdict(lambda: 100)
class Solution(object):                
    def isequalpt(self, p1, p2):
        if p1.x == p2.x and p1.y == p2.y:
            return True
        else:
            return False
    def maxPointsatPoint(self, points):
        pt = points[0]
        del points[0]
        i = 0
        maxnum = 0
        same = 1
        dic = defaultdict(lambda: 0)
        while i < len(points):
            p = points[i]
            if self.isequalpt(pt, p):
                same += 1
                # 并且把p删除
                points.remove(p)
                continue
            if pt.x != p.x:
                k = (p.y-pt.y)*np.longdouble(1)/(p.x-pt.x)
                dic[k] += 1
                maxnum = max(maxnum, dic[k])
            else:
                dic['zero'] += 1
                maxnum = max(maxnum, dic['zero'])
            i += 1
        maxnum += same
        return maxnum
     
    def maxPoints(self, points):
        """
        :type points: List[Point]
        :rtype: int
        """
        lens = len(points)  
        print lens
        if lens < 3:
            return lens
        self.dic=None
        self.maxnumAll = 0
        i = 0
        while lens > 2:
            lr = self.maxPointsatPoint(points)
            self.maxnumAll = max(self.maxnumAll, lr)
            lens = len(points)
        
        return self.maxnumAll