From 7a4057066a52a68b60e1c19670a5f21b5ffa716c Mon Sep 17 00:00:00 2001
From: StriveDD <Kip2021czb@gmail.com>
Date: Thu, 2 Mar 2023 11:15:07 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0841.=E9=92=A5=E5=8C=99?=
 =?UTF-8?q?=E5=92=8C=E6=88=BF=E9=97=B4=E7=9A=84Java=E7=89=88=E6=9C=AC?=
 =?UTF-8?q?=E7=9A=84BFS=E4=BB=A3=E7=A0=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 problems/0841.钥匙和房间.md | 43 ++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/problems/0841.钥匙和房间.md b/problems/0841.钥匙和房间.md
index a973ab56..00263cac 100644
--- a/problems/0841.钥匙和房间.md
+++ b/problems/0841.钥匙和房间.md
@@ -273,6 +273,48 @@ class Solution {
         return true;
     }
 }
+
+// 广度优先搜索
+class Solution {
+    public boolean canVisitAllRooms(List<List<Integer>> rooms) {
+        boolean[] visited = new boolean[rooms.size()];    // 用一个 visited 数据记录房间是否被访问
+        visited[0] = true;
+        Queue<Integer> queue = new ArrayDeque<>();
+        queue.add(0);           // 第 0 个房间标记为已访问
+        while (!queue.isEmpty()) {
+            int curKey = queue.poll();
+            for (int key: rooms.get(curKey)) {
+                if (visited[key]) continue;
+                visited[key] = true;
+                queue.add(key);
+            }
+        }
+        for (boolean key: visited)
+            if (!key) return false;
+        return true;
+    }
+}
+
+// 广度优先遍历(时间优化)
+class Solution {
+    public boolean canVisitAllRooms(List<List<Integer>> rooms) {
+        int count = 1;      // 用来记录可以被访问的房间数目，因为初始状态下 0 号房间可以被访问，所以置为 1
+        boolean[] visited = new boolean[rooms.size()];      // 用一个 visited 数据记录房间是否被访问
+        visited[0] = true;          // 第 0 个房间标记为已访问
+        Queue<Integer> queue = new ArrayDeque<>();
+        queue.add(0);
+        while (!queue.isEmpty()) {
+            int curKey = queue.poll();
+            for (int key: rooms.get(curKey)) {
+                if (visited[key]) continue;
+                ++count;                // 每访问一个访问房间就让 count 加 1
+                visited[key] = true;
+                queue.add(key);
+            }
+        }
+        return count == rooms.size();       // 如果 count 等于房间数目，表示能进入所有房间，反之不能
+    }
+}
 ```
 
 ### python3
@@ -417,3 +459,4 @@ function canVisitAllRooms(rooms: number[][]): boolean {
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
+