leetcode-159周赛-5230-缀点成线

自己的提交：

class Solution:
    def checkStraightLine(self, coordinates: List[List[int]]) -> bool:
        if not coordinates: return False
        if len(coordinates) <= 2:
            return True
        k = float("inf") if coordinates[1][0] - coordinates[0][0] == 0 else (coordinates[1][1] - coordinates[0][1]) / (coordinates[1][0] - coordinates[0][0])
        for i in range(2,len(coordinates)):
            k1 = float("inf") if coordinates[i][0] - coordinates[i-1][0] == 0 else (coordinates[i][1] - coordinates[i-1][1]) / (coordinates[i][0] - coordinates[i-1][0])
            if k1 != k:
                return False
        return True

另：

class Solution:
    def checkStraightLine(self, coordinates: List[List[int]]) -> bool:
        n = len(coordinates)
        if n <= 2:
            return True
        x1, y1 = coordinates[0][0] - coordinates[1][0], coordinates[0][1] - coordinates[1][1]
        for i in range(2, n):
            x2, y2 = coordinates[0][0] - coordinates[i][0], coordinates[0][1] - coordinates[i][1]
            if x1 * y2 - x2 * y1 != 0:
                return False
        return True