Shortest Bridge
You are given an n x n binary matrix grid where 1 represents land and 0 represents water.
An island is a 4-directionally connected group of 1's not connected to any other 1's. There are exactly two islands in grid.
You may change 0's to 1's to connect the two islands to form one island.
Return the smallest number of 0's you must flip to connect the two islands.
Example 1
0 1 1 0
Input
grid = [[0,1],[1,0]]Output
1Flipping one water cell connects the two diagonal land cells into one island.
Example 2
0 1 0 0 0 0 0 0 1
Input
grid = [[0,1,0],[0,0,0],[0,0,1]]Output
2Flipping two water cells creates a path connecting the two islands.
Constraints
- n == grid.length == grid[i].length
- 2 <= n <= 100
- grid[i][j] is either 0 or 1.
- There are exactly two islands in grid.