(This question has been seen in the interviews of the following companies: Google)

Given a binary grid where 0 represents water and 1 represents land. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. Delete all islands except their borders. A border is land adjacent to water. You may assume all four edges of the grid are surrounded by water.

Example 1:

``````Input:
[[0, 0, 0, 1, 1, 1],
[0, 0, 0, 1, 1, 1],
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1]]

Output:
[[0, 0, 0, 1, 1, 1],
[0, 0, 0, 1, 0, 1],
[1, 1, 1, 1, 0, 1],
[1, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1]]
``````
Example 2:
``````Input:
[[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1]]

Output:
[[1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1]]
``````
Example 3:
``````Input:
[[1, 1, 1, 0, 1, 1, 1],
[1, 1, 1, 0, 1, 1, 1],
[1, 1, 1, 0, 1, 1, 1],
[0, 0, 0, 0, 1, 1, 1],
[1, 1, 1, 0, 1, 1, 1]]

Output:
[[1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 0, 1, 0, 1],
[1, 1, 1, 0, 1, 0, 1],
[0, 0, 0, 0, 1, 0, 1],
[1, 1, 1, 0, 1, 1, 1]]
``````