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.

y = ax + b 형태를 이용해서 점마다 기울기 구해서 하면 될 거 같기도 한데...

이 기울기를 모든 조합으로 구하는게... 못하겠읍니다

Solution 1: Runtime: 48 ms - 96.96% / Memory Usage: 14 MB - 99.22%

class Solution:
    def maxPoints(self, points: List[List[int]]) -> int:
        def helper(currentPoint, points):
            slopes,duplicates,ans = {},0,0
            x1, y1 = currentPoint
            for x2, y2 in points:
                # If the points are same inc duplicate counter
                if x1 == x2 and y1 == y2:
                    duplicates += 1
                # else find the slop and add in dic
                else:
                    slope = (x2 - x1) / (y2 - y1) if y2 != y1 else 'inf'
                    count = slopes.get(slope, 0) + 1
                    slopes[slope] = count
                    ans = max(ans, count)
            return ans + 1 + duplicates
        ans = 0
        while points:
            currentPoint = points.pop()
            ans = max(ans, helper(currentPoint, points))
        return ans

point 를 하나씩 pop 해서 currentPoint 로 잡고 (x1)
남은 point 들을 x2 로 잡아서 중복 확인 및 기울기 구하기

• get(a, b) => a 를 찾고 없으면 default 값 = b 가 됨