[Leetcode] Max Points on a Line, leetcodepoints

[Leetcode] Max Points on a Line, leetcodepoints
Max Points on a Line description:

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

Solution:

1. First, an O (n ^ 3) method is used to calculate the equation (n ^ 2) of each line, and then determine the number of points on each line (N ). This method must be feasible, but the complexity is too high.
2. then we think of an O (N), and calculate the slope of this vertex and all other vertices for each vertex, which is a straight line composed of the points with the same slope, is a straight line with the most vertices.

Note:

1.Point of coincidence
2.Point where the slope does not exist

 1 # Definition for a point 2 class Point: 3     def __init__(self, a=0, b=0): 4         self.x = a 5         self.y = b 6  7 class Solution: 8     # @param points, a list of Points 9     # @return an integer10     def calcK(self,pa, pb):11         t = ((pb.y - pa.y) * 1.0) / (pb.x - pa.x)12         return t13         14     def maxPoints(self, points):15         l = len(points)16         res = 017         if l <= 2:18             return l 19         for i in xrange(l):20             same = 021             k = {}22             k['inf'] = 023             for j in xrange(l):24                 if points[j].x == points[i].x and points[j].y != points[i].y:25                     k['inf'] += 126                 elif points[j].x == points[i].x and points[j].y == points[i].y:27                     same +=128                 else:29                     t = self.calcK(points[j],points[i])30                     if t not in k.keys():31                         k[t] = 132                     else:33                         k[t] += 134             res = max(res, max(k.values())+same)35         return res36         37 def main():38     points = []39     points.append(Point(0,0))40     points.append(Point(1,1))41     points.append(Point(1,-1))42     #points.append(Point(0,0))43     #points.append(Point(1,1))44     #points.append(Point(0,0))45     s = Solution()46     print s.maxPoints(points)47     48     49 if __name__ == '__main__':50     main()51