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 ~0~.