Maximum number of points on the line ----- hash table solution

Title Description

Give you an array points , among points[i] = [xi, yi] Express X-Y A point on the plane . Find out how many points are in the same line at most .

Example 1：

	 Input ：points = [[1,1],[2,2],[3,3]]
	 Output ：3

Example 2：

Tips ：

	 Input ：points = [[1,1],[3,2],[5,3],[4,1],[2,3],[1,4]]
	 Output ：4

1 <= points.length <= 300
points[i].length == 2
-104 <= xi, yi <= 104
points All the points in Different from each other

Their thinking

Let's start with a question , What are the conditions on the same line ？

The slope of the straight line formed by each point on the straight line is equal

Let's do a double-layer traversal , The outer layer traverses the entire point array , The group of points after the inner layer traverses the position of the outer point , By finding the formula for the slope , Build a hash table , Record the number of slope occurrences in the table , After inner layer traversal , Find the slope with the most occurrences , This is the number of points with the largest number of lines headed by the outer point position （+1）.

Code

Stick the leetcode Pass code

class Solution:
    def maxPoints(self, points: List[List[int]]) -> int:
        answer=0
        for i in range(len(points)):
            temp_dict=dict()
            for j in range(i+1,len(points)):
                if (points[j][0]-points[i][0])==0:
                    temp="*"
                else:
                    temp=(points[j][1]-points[i][1])/(points[j][0]-points[i][0])
                if temp not in temp_dict:
                    temp_dict[temp]=1
                else:
                    temp_dict[temp]+=1
            if len(temp_dict)!=0:
                b=max(temp_dict.values())
                answer=max(b,answer)
        return answer+1