1. class Solution:
    2.     def uniquePathsWithObstacles(self, obstacleGrid: List[List[int]]) -> int:
    3.         if not obstacleGrid:
    4.             return 0
    5.         m = len(obstacleGrid)
    6.         n = len(obstacleGrid[0])
    10.         result = [[0] * (n + 1) for _ in range(m + 1)]
    13.         result[0][1] = 1
    14.         for i in range(1, m + 1):
    15.             for j in range(1, n + 1):
    16.                 if obstacleGrid[i-1][j-1] == 0:
    17.                     result[i][j] = result[i-1][j] + result[i][j-1]
    18.         return result[-1][-1]