代码随想录day39|62. 不同路径63. 不同路径 II

62. 不同路径

class Solution:
    def uniquePaths(self, m: int, n: int) -> int:
        dp = [[0] * n for _ in range(m)]
        for i in range(m):
            dp[i][0] = 1
        for j in range(n):
            dp[0][j] = 1
        for i in range(1,m):
            for j in range(1,n):
                dp[i][j] = dp[i-1][j] +dp[i][j-1]
        return dp[m-1][n-1]

63. 不同路径 II

class Solution:
    def uniquePathsWithObstacles(self, obstacleGrid: List[List[int]]) -> int:
        m=len(obstacleGrid)
        n=len(obstacleGrid[0])
        dp = [[0] * n for _ in range(m)]
        for i in range(m):
            if obstacleGrid[i][0] == 0:
                dp[i][0] = 1
            else:
                break
        for j in range(n):
            if obstacleGrid[0][j] == 0:
                dp[0][j] = 1
            else:
                break
        for i in range(1,m):
            for j in range(1,n):
                if obstacleGrid[i][j] == 0:
                    dp[i][j] = dp[i-1][j] +dp[i][j-1]
        return  dp[m-1][n-1]