added java file

Author: Amrutha26

MaxAreaOfIsland.java

@@ -0,0 +1,32 @@
+// https://leetcode.com/problems/max-area-of-island/
+
+
+class Solution {
+    public int maxAreaOfIsland(int[][] grid) {
+        int max = 0;
+        for(int i=0; i<grid.length; i++) {
+            for(int j=0; j<grid[i].length; j++) {
+                if(grid[i][j] == 1) {
+                    max = Math.max(max, dfs(grid, i, j));
+                }
+            }
+        }
+        
+        return max;
+    }
+    
+    public int dfs(int[][] grid, int i, int j) {
+        if(i < 0 || i>= grid.length || j < 0 || j >= grid[i].length || grid[i][j] == 0) {
+            return 0;
+        }
+        
+        grid[i][j] = 0;
+        int count = 1;
+        count += dfs(grid, i + 1, j);
+        count += dfs(grid, i - 1, j);
+        count += dfs(grid, i, j + 1);
+        count += dfs(grid, i, j - 1);
+        
+        return count;
+    }
+}