You are given a m x n 2D grid initialized with these three possible values.
-1
- A wall or an obstacle.
0
- A gate.
INF
- Infinity means an empty room. We use the value
2
31
- 1 = 2147483647
to represent
INF
as you may assume that the distance to a gate is less than
2147483647
.
Fill each empty room with the distance to its
nearest
gate. If it is impossible to reach a gate, it should be filled with
INF
.
Example:
Given the 2D grid:
INF -1 0 INF INF INF INF -1 INF -1 INF -1 0 -1 INF INF
After running your function, the 2D grid should be:
3 -1 0 1 2 2 1 -1 1 -1 2 -1 0 -1 3 4