View Compilation Error

0_0_39004478_29969.cpp:23:1: error: 'vis' does not name a type
   23 | vis[x]=false;
      | ^~~
0_0_39004478_29969.cpp: In function 'int main()':
0_0_39004478_29969.cpp:33:17: error: 'dfs' was not declared in this scope
   33 |                 dfs(a,b,0);
      |                 ^~~