As Far from Land as Possible
Given an n x n grid containing only values 0 and 1, where 0 represents water and 1 represents land, find a water cell such that its distance to the nearest land cell is maximized, and return the distance. If no land or water exists in the grid, return -1.
The distance used in this problem is the Manhattan distance: the distance between two cells (x0, y0) and (x1, y1) is |x0 - x1| + |y0 - y1|.
Example 1
1 0 1 0 0 0 1 0 1
Input
grid = [[1,0,1],[0,0,0],[1,0,1]]Output
2The cell (1, 1) is as far as possible from all the land with distance 2.
Example 2
1 0 0 0 0 0 0 0 0
Input
grid = [[1,0,0],[0,0,0],[0,0,0]]Output
4The cell (2, 2) is as far as possible from all the land with distance 4.
Constraints
- n == grid.length
- n == grid[i].length
- 1 <= n <= 100
- grid[i][j] is 0 or 1