Max Points on a Line Leetcode Python

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

这道题做的时候要考虑几个edge 

1. infinity

2. same points

这里我们用hashtable将得到的slope存起来，最后每过一个点将其和其他所有点的组合成的slope数量进行比较最后得到最大值。

算法复杂度是o(n^2) 空间复杂度是O(n)

代码如下：

# Definition for a point
# class Point:
# def __init__(self, a=0, b=0):
# self.x = a
# self.y = b

class Solution:
# @param points, a list of Points
# @return an integer
def maxPoints(self, points):
#slop={}
maxp=0
if len(points)<3:
return len(points)
for i in range(len(points)):
samepoint=1
slope={'inf':0}
for j in range(len(points)):
if i==j:
continue
elif points[i].x==points[j].x and points[i].y==points[j].y:
samepoint+=1
elif points[i].x==points[j].x and points[i].y!=points[j].y:
slope['inf']+=1
else:
k=1.0*(points[i].y-points[j].y)/(points[i].x-points[j].x)
if k not in slope:
slope[k]=1
else:
slope[k]+=1
maxp=max(maxp,max(slope.values())+samepoint)
return maxp