Counting grid paths around obstacles
Asked at Akuna Capital
A robot starts at the top-left cell of a grid and moves only right or down to reach the bottom-right cell. Some cells are blocked (marked 1) and cannot be entered.
grid = [[0, 0, 0],
[0, 1, 0],
[0, 0, 0]]
-> 2 # 1 = blocked; two clear paths remain
Return the number of distinct clear paths. Aim for .
Show a hint
The number of ways to reach a cell is the number of ways to reach the cell above it plus the cell to its left. A blocked cell contributes zero ways.
Your answer
This one is open-ended. Work it through, then check your reasoning against the full solution.