Leetcode 200 | Number of Islands | DFS (Java Solution)

Number of Islands is a google interview question and is classical dfs problem.
It is present on leetcode as 200. Asked in big tech interview like google, amazon, microsoft etc.

Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

#leetcode #thetechgranth #numberofisland

Example 1:

Input: grid = [
["1","1","1","1","0"],
["1","1","0","1","0"],
["1","1","0","0","0"],
["0","0","0","0","0"]
]
Output: 1
Example 2:

Input: grid = [
["1","1","0","0","0"],
["1","1","0","0","0"],
["0","0","1","0","0"],
["0","0","0","1","1"]
]
Output: 3

[Shanerdigans]

Tried this solution and one of my own and all testcases do not pass.

Failure -
[[1, 0, 0, 1], [0, 1, 1, 0], [0, 1, 1, 1], [1, 0, 1, 1]]