```cpp
if(flag[first][second][key-1]&&flag[second][third][key-1]){
flag[first][second][key]=true;
dist[first][second]=1;
};
```
这里的更新错了
应该是
```cpp
if(flag[first][second][key-1]&&flag[second][third][key-1]){
flag[first][third][key]=true;
dist[first][third]=1;
};
```
by sunfather @ 2024-02-02 08:30:40