695. 岛屿的最大面积

Author: houfachao

Diff for: src/main/java/com/geekidentity/leetcode/n0695/MaxAreaOfIsland.java

@@ -0,0 +1,31 @@
+package com.geekidentity.leetcode.n0695;
+
+public class MaxAreaOfIsland {
+    public int maxAreaOfIsland(int[][] grid) {
+        int maxArea = 0;
+        for (int row = 0; row < grid.length; row++) {
+            for (int col = 0; col < grid[0].length; col++) {
+                if (grid[row][col] == 1) {
+                    int area = area(grid, row, col);
+                    maxArea = Math.max(area, maxArea);
+                }
+            }
+        }
+        return maxArea;
+    }
+
+    public int area(int[][] grid, int row, int col) {
+        if (!inArea(grid, row, col)) return 0;
+        if (grid[row][col] != 1) return 0;
+        grid[row][col] = 2;
+        return 1 +
+                area(grid, row - 1, col) +
+                area(grid, row + 1, col) +
+                area(grid, row, col - 1) +
+                area(grid, row, col + 1);
+    }
+
+    public boolean inArea(int[][] grid, int row, int col) {
+        return 0 <= row && row < grid.length && 0 <= col && col < grid[0].length;
+    }
+}