From 6a201720030faa7a70abcc313c1aa756245f3329 Mon Sep 17 00:00:00 2001
From: AronJudge <2286381138@qq.com>
Date: Sat, 20 Aug 2022 10:38:58 +0800
Subject: [PATCH] =?UTF-8?q?463=20=E5=B2=9B=E5=B1=BF=E7=9A=84=E5=91=A8?=
 =?UTF-8?q?=E9=95=BF?=
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更新Java的方法二
---
 problems/0463.岛屿的周长.md | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/problems/0463.岛屿的周长.md b/problems/0463.岛屿的周长.md
index ea038140..3dc69f20 100644
--- a/problems/0463.岛屿的周长.md
+++ b/problems/0463.岛屿的周长.md
@@ -118,6 +118,27 @@ class Solution {
         return res;
     }
 }
+
+// 解法二
+class Solution {
+    public int islandPerimeter(int[][] grid) {
+        // 计算岛屿的周长 
+        // 方法二 : 遇到相邻的陆地总周长就-2
+        int landSum = 0; // 陆地数量 
+        int cover = 0; // 相邻陆地数量
+        for (int i = 0; i < grid.length; i++) {
+            for (int j = 0; j < grid[0].length; j++) {
+                if (grid[i][j] == 1) {
+                    landSum++;
+                    // 统计上面和左边的相邻陆地
+                    if(i - 1 >= 0 && grid[i-1][j] == 1) cover++;
+                    if(j - 1 >= 0 && grid[i][j-1] == 1) cover++;
+                }
+            }
+        }
+        return landSum * 4 - cover * 2;
+    }
+}
 ```
 
 Python：