Paste_Image.png

簡單的動態規劃

class Solution(object):
    def uniquePaths(self, m, n):
        """
        :type m: int
        :type n: int
        :rtype: int
        """
        # set 0 row to 1
        arr = [[1 for i in range(n) ]]
        #count
        for i in range(1,m):
            for j in range(n):
                if j == 0:
                    arr.append([1])
                    continue
                arr[i].append((arr[i-1][j] + arr[i][j-1]))
        return arr[m-1][n-1]

s = Solution()
print(s.uniquePaths(1,2))