39天【程式碼隨想錄演算法訓練營34期】第九章 動態規劃part02（● 62.不同路徑 ● 63. 不同路徑 II ）

62.不同路徑

class Solution:
    def uniquePaths(self, m: int, n: int) -> int:
        table = [[0]*n]*m

        for x in range(n):
            table[0][x] = 1
        for y in range(m):
            table[y][0] = 1
        
        for y in range(1, m):
            for x in range(1, n):
                table[y][x] = table[y-1][x] + table[y][x-1]

        return table[-1][-1]

63. 不同路徑 II

class Solution:
    def uniquePathsWithObstacles(self, obstacleGrid: List[List[int]]) -> int:
        m = len(obstacleGrid)
        n = len(obstacleGrid[0])

        if obstacleGrid[m - 1][n - 1] == 1 or obstacleGrid[0][0] == 1:
            return 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] == 1:
                    continue
                else:
                    dp[i][j] = dp[i-1][j] + dp[i][j-1]
    
        return dp[m-1][n-1]