leetcode 695 Max Area of Island

class Solution {        public int maxAreaOfIsland(int[][] grid) {          int max_air=0;            for(int i=0;i<grid.length;i++){                for(int j=0;j<grid[0].length;j++){                    if(grid[i][j]==1) max_air=Math.max(max_air,maxair(grid,i,j));                }            }            return max_air;        }                                                               public int maxair(int[][] grid,int i,int j){            if(i >=0 && i<grid.length && j>=0 && j<grid[0].length && grid[i][j]==1){                grid[i][j]=0;                return 1+maxair(grid,i+1,j)+maxair(grid,i-1,j)+maxair(grid,i,j+1)+maxair(grid,i,j-1);            }                    return 0;        }       }