Problem
Follow up for “Unique Paths”:
Now consider if some obstacles are added to the grids. How many unique paths would there be?
An obstacle and empty space is marked as
1 and 0 respectively in the grid.For example,
There is one obstacle in the middle of a 3×3 grid as illustrated below.
[
[0,0,0],
[0,1,0],
[0,0,0]
]
The total number of unique paths is
2.Note: m and n will be at most 100.
Analysis
- Similar to Unique Path except that we need to decide whether a position has obstacle or not
- If yes, the number of ways to it is 0