题目：

题解：

class Solution:
    def uniquePathsWithObstacles(self, obstacleGrid: List[List[int]]) -> int:
        row = len(obstacleGrid)
        col = len(obstacleGrid[0])
        dp = [[0]*col for _ in range(row)]

        for i in range(row):
            for j in range(col):
                if not obstacleGrid[i][j]:
                    if i == j == 0:
                        dp[i][j] = 1
                    else:
                        up = dp[i-1][j] if i>0 else 0
                        left = dp[i][j-1] if j>0 else 0
                        dp[i][j] = up + left
        return dp[-1][-1]