Max Area of Island

Medium

Given an m x n binary grid, return the area (number of cells) of the largest island. Cells connect horizontally or vertically. If there is no island, return 0.

Example 1

Input:  grid = [[0,0,1,0],[1,1,1,0],[0,1,0,0]]
Output: 5

Example 2

Input:  grid = [[0,0,0],[0,0,0]]
Output: 0

Constraints

• 1 <= m, n <= 50
• grid[i][j] is 0 or 1.