leetcode 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.

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思路

给出平面上的几个点，求出同在一条直线上的点最多的个数

两个for循环，求两个点之间的斜率，注意垂直于x轴的斜率的表示以及覆盖点的个数[0,0]和[0,0]是两个点

class Point(object):
def __init__(self,a=0,b=0):
self.x=a
self.y=b
class Solution(object):
def maxPoints(self,points):
Lenth=len(points)
if not Lenth:
return 0
Max_=0
for i in range(Lenth-1):
dict={}
count=0
for j in range(i+1,Lenth):
if points[i].x-points[j].x==0:
if points[i].y==points[j].y:
count=count+1
dict.setdefault('b',0)
else:
if 'a' not in dict:
dict.setdefault('a',1)
else:
dict['a']=dict['a']+1
else:
k=(points[j].y-points[i].y)*1.0/(points[j].x-points[i].x)
if k not in dict:
dict.setdefault(k,1)
else:
dict[k]=dict[k]+1
#print dict
Max_=max(Max_,max(dict.items(),key=lambda x:x[1])[1]+count)
return (Max_+1)