You are given an
m x n binary matrix
grid. An island is a group of
1's (representing land) connected 4-directionally (horizontal or vertical.) You may assume all four edges of the grid are surrounded by water.
The area of an island is the number of cells with a value
1 in the island.
Return the maximum area of an island in
grid. If there is no island, return
Input: grid = [[0,0,1,0,0,0,0,1,0,0,0,0,0],[0,0,0,0,0,0,0,1,1,1,0,0,0],[0,1,1,0,1,0,0,0,0,0,0,0,0],[0,1,0,0,1,1,0,0,1,0,1,0,0],[0,1,0,0,1,1,0,0,1,1,1,0,0],[0,0,0,0,0,0,0,0,0,0,1,0,0],[0,0,0,0,0,0,0,1,1,1,0,0,0],[0,0,0,0,0,0,0,1,1,0,0,0,0]] Output: 6 Explanation: The answer is not 11, because the island must be connected 4-directionally.
Input: grid = [[0,0,0,0,0,0,0,0]] Output: 0
m == grid.length
n == grid[i].length
1 <= m, n <= 50