CCI 9.2 机器人移动路径

摄像有个机器人坐在X*Y网格的左上角，只能想右、向下移动。机器人从(0,0)到(X,Y)有多少种走法？

进阶

假设有些点为“禁区”，机器人不能踏足。设计一种算法，找出一条路径，让机器人从左上角移动到右下角。

这道题跟LeetCode上的Unique Paths 和Unique Paths II一样。

Unique Paths

A robot is located at the top-left corner of a m X n grid(marked 'Start' in the diagram below).

The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of thr grid(marked 'Finish' in the diagram below).

How many possible unique paths are there?

NOTE: m and n will be at mo