From 70129fb6b6678294f1d3c278eb17880a5b038284 Mon Sep 17 00:00:00 2001
From: Zengtudor <zengtudor@outlook.com>
Date: Fri, 11 Oct 2024 16:57:29 +0800
Subject: [PATCH] update

---
 README.md             | 10 ++++++++++
 src/oj4980/oj4980.cpp |  8 +++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 5abf72d..f4b8271 100755
--- a/README.md
+++ b/README.md
@@ -1,3 +1,13 @@
 # algorithm_2024
 
 algorithm_2024
+
+## 错题本
+
+### Luogu某题
+
+#### 数组越界导致变量异常更改
+
+### [OJ4980:拯救行动](http://noi.openjudge.cn/ch0205/4980/)
+
+#### 未考虑无答案（特殊情况）时输出
\ No newline at end of file
diff --git a/src/oj4980/oj4980.cpp b/src/oj4980/oj4980.cpp
index 0d4e53a..638facc 100644
--- a/src/oj4980/oj4980.cpp
+++ b/src/oj4980/oj4980.cpp
@@ -21,7 +21,8 @@ struct Status{
 };
 
 const ll max_nm {200+5};
-ll n, h, w, ans{std::numeric_limits<decltype(ans)>::max()};
+const ll ll_max {std::numeric_limits<decltype(ll_max)>::max()};
+ll n, h, w, ans{ll_max};
 char map[max_nm][max_nm];
 Point me;
 
@@ -36,7 +37,7 @@ void bfs(const Point start)noexcept{
     std::bitset<max_nm> vis[max_nm];
 
     std::priority_queue<Status> q;
-    ans = std::numeric_limits<decltype(ans)>::max();
+    ans = ll_max;
     vis[start.x][start.y] = true;
 
     q.push({start,0});
@@ -76,6 +77,7 @@ int main(){
             }
         }
         bfs(me);
-        os<<ans<<'\n';
+        if(ans==ll_max)os<<"Impossible\n";
+        else os<<ans<<'\n';
     }
 }
\ No newline at end of file