Problems/1162. As Far from Land as Possible
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1162. As Far from Land as Possible

MediumMatrixGraphBFS

Given an n x n grid containing only 0 (representing water) and 1 (representing land), locate a water cell such that its distance to the nearest land cell is maximized, and return that maximum distance. If no land or no water exists in the grid, return -1.

The distance used here is the Manhattan distance: the distance between two cells (x0, y0) and (x1, y1) is |x0 - x1| + |y0 - y1|.

Example 1
Input: grid = [ [1, 0, 1], [0, 0, 0], [1, 0, 1] ]
Output: 2
The water cell at (1,1) is at distance 2 from all four land cells at the corners, which is the maximum possible distance.
Example 2
Input: grid = [ [1, 0], [0, 0] ]
Output: 2
The water cell at (1,1) is at distance 2 from the only land cell at (0,0).
Example 3
Input: grid = [ [1, 1], [1, 1] ]
Output: -1
Since there are no water cells in the grid, we return -1.
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