You are given an array coordinates, coordinates[i] = [x, y], where [x, y] represents the coordinate of a point. Check if these points make a straight line in the XY plane.
Example 1:
Input: coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
Output: true
Example 2:
Input: coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]
Output: false
Constraints:
2 <= coordinates.length <= 1000coordinates[i].length == 2-10^4 <= coordinates[i][0], coordinates[i][1] <= 10^4coordinatescontains no duplicate point.
Solution
这个题比较直接，我们只需要比较这些点构成的斜率是不是一样，如果是那么它们就在同一条直线上，计算斜率的方法就还是用任意两点的y值，除以它们对应的x值 考虑到分母可能为0，我们可以用2个变量，分别计算y2-y1 和x2-x1,
class Solution:
def checkStraightLine(self, coordinates: List[List[int]]) -> bool:
dy = (coordinates[1][1] - coordinates[0][1])
dx = (coordinates[1][0] - coordinates[0][0])
for i in range(2,len(coordinates)):
dyp = (coordinates[i][1] - coordinates[1][1])
dxp = (coordinates[i][0] - coordinates[1][0])
if dy* dxp!= dx * dyp:
return False
return True;
