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[Google Phone] Delete Islands

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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]]



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