foo.cc: In function ‘void fohuj()’:
foo.cc:18:30: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   18 |                 for(int i=0;i<b[x].size();i++)qa[b[x][i]]--;
      |                             ~^~~~~~~~~~~~
foo.cc:20:72: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   20 |                 for(int i=1;i<=n;i++){if(qa[i]==1){flag=1;for(int j=0;j<a[i].size();j++)if(!vis[a[i][j]]){p.push(a[i][j]);ans[i]=a[i][j];vis2[i]=1;qj++;break;}break;}}
      |                                                                       ~^~~~~~~~~~~~
foo.cc:20:138: error: ‘vis2’ was not declared in this scope; did you mean ‘vis’?
   20 |                 for(int i=1;i<=n;i++){if(qa[i]==1){flag=1;for(int j=0;j<a[i].size();j++)if(!vis[a[i][j]]){p.push(a[i][j]);ans[i]=a[i][j];vis2[i]=1;qj++;break;}break;}}
      |                                                                                                                                          ^~~~
      |                                                                                                                                          vis