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.
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|
.
If no land or water exists in the grid, return -1
.
Example 1:
Input: [[1,0,1],[0,0,0],[1,0,1]] Output: 2 Explanation: The cell (1, 1) is as far as possible from all the land with distance 2.
Example 2:
Input: [[1,0,0],[0,0,0],[0,0,0]] Output: 4 Explanation: The cell (2, 2) is as far as possible from all the land with distance 4.
Note:
1 <= grid.length == grid[0].length <= 100
grid[i][j]
is 0
or 1