Max Area of Island

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.

Example 1:

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.

Example 2:

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

Constraints:

• m == grid.length

• n == grid[i].length

• 1 <= m, n <= 50

• grid[i][j] is either 0 or 1.

public class Solution {
    public int MaxAreaOfIsland(int[][] grid)
    {
        int maxArea = 0;
        int n = grid.Length;
        int m = grid[0].Length;
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < m; j++)
            {
                if (grid[i][j] == 1)
                {
                    int area = GetAreaOfIsland(grid, n, m, i, j);
                    maxArea = Math.Max(maxArea, area);
                }
            }

        }
        return maxArea;

    }

     public int GetAreaOfIsland(int[][] grid, int n, int m, int i, int j)
    {
        if (i >= 0 && i < n && j >= 0 && j < m && grid[i][j] == 1)
        {
            grid[i][j] = 0;
            return 1 + GetAreaOfIsland(grid, n, m, i + 1, j) + GetAreaOfIsland(grid, n, m, i - 1, j) + GetAreaOfIsland(grid, n, m, i, j + 1) + GetAreaOfIsland(grid, n, m, i, j - 1);
        }
        return 0;   
    }
}