代码随想录算法训练营day39| 62. 不同路径、63. 不同路径II

62、不同路径：

class Solution(object):
    def uniquePaths(self, m, n):
        """
        :type m: int
        :type n: int
        :rtype: 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(object):
    def uniquePathsWithObstacles(self, obstacleGrid):
        """
        :type obstacleGrid: List[List[int]]
        :rtype: int
        """
        m = len(obstacleGrid)
        n = len(obstacleGrid[0])
        if obstacleGrid[0][0] == 1:
            return 0
        dp = [[0]*n for _ in range(m)]
        dp[0][0] = 1
        for i in range(m):
            for j in range(n):
                if i == j == 0:
                    continue
                elif obstacleGrid[i][j] == 1:
                    dp[i][j] = 0
                elif j == 0 and i > 0:
                    dp[i][j] = dp[i-1][j]
                elif i == 0 and j > 0:
                    dp[i][j] = dp[i][j-1]
                else:
                    dp[i][j] = dp[i-1][j] + dp[i][j-1]
        return dp[m-1][n-1]