update

README.md

@@ -12,7 +12,21 @@ algorithm_2024
 
 #### 未考虑无答案（特殊情况）时输出
 
-#### 优先对联是从大到小排序，重载运算符时需反向或者std::greater
+#### 优先队列是从大到小排序，重载运算符时需反向或者std::greater
+```cpp
+for(ll i{0};i<4;i++){
+    const Point next {status.now.x+to_next[i][0],status.now.y+to_next[i][1]};
+    if(vis[next.x][next.y])continue;
+    const auto nextchar = [&next]()->char{return map[next.x][next.y];};
+    ll cost {1};
+    if(next.x>h || next.x<=0 || next.y > w || next.y<=0 
+    || nextchar()=='#')continue;
+    if(nextchar()=='x')cost++; // 因为这里有可能会遇到士兵，会改变最优解顺序，要使用priority_queue
+    const Status next_status {next,status.step+cost};
+    vis[next_status.now.x][next_status.now.y] = true;
+    q.push(next_status);
+}
+```
 ```cpp
 struct Status{
     Point now;

src/oj4980/oj4980.cpp

@@ -57,7 +57,7 @@ void bfs(const Point start)noexcept{
             ll cost {1};
             if(next.x>h || next.x<=0 || next.y > w || next.y<=0 
             || nextchar()=='#')continue;
-            if(nextchar()=='x')cost++;
+            if(nextchar()=='x')cost++; // 因为这里有可能会遇到士兵，会改变最优解顺序，要使用priority_queue
             const Status next_status {next,status.step+cost};
             vis[next_status.now.x][next_status.now.y] = true;
             q.push(next_status);