From ad3aecc7f3d8f5033bcacce86d68a2a420893f1c Mon Sep 17 00:00:00 2001
From: xsduan98 <xsduan1998@163.com>
Date: Sun, 12 Sep 2021 20:53:53 +0800
Subject: [PATCH] =?UTF-8?q?463.=E5=B2=9B=E5=B1=BF=E7=9A=84=E5=91=A8?=
 =?UTF-8?q?=E9=95=BF=20=E6=B7=BB=E5=8A=A0Java=E7=89=88=E6=9C=AC?=
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---
 problems/0463.岛屿的周长.md | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/problems/0463.岛屿的周长.md b/problems/0463.岛屿的周长.md
index 18654758..609c25a5 100644
--- a/problems/0463.岛屿的周长.md
+++ b/problems/0463.岛屿的周长.md
@@ -84,6 +84,37 @@ public:
 
 Java： 
 
+```java
+// 解法一
+class Solution {
+    // 上下左右 4 个方向
+    int[] dirx = {-1, 1, 0, 0};
+    int[] diry = {0, 0, -1, 1};
+
+    public int islandPerimeter(int[][] grid) {
+        int m = grid.length;
+        int n = grid[0].length;
+        int res = 0; // 岛屿周长
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                if (grid[i][j] == 1) {
+                    for (int k = 0; k < 4; k++) {
+                        int x = i + dirx[k];
+                        int y = j + diry[k];
+                        // 当前位置是陆地，并且从当前位置4个方向扩展的“新位置”是“水域”或“新位置“越界，则会为周长贡献一条边
+                        if (x < 0 || x >= m || y < 0 || y >= n || grid[x][y] == 0) {
+                            res++;
+                            continue;
+                        }
+                    }
+                }
+            }
+        }
+        return res;
+    }
+}
+```
+
 Python：
 
 Go：