train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:18:12: error: request for member 'push_back' in 'u.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
18 | #define pb push_back
| ^~~~~~~~~
train.cpp:35:39: note: in expansion of macro 'pb'
35 | for(int i = 0; i < m; i++) E[u[i].pb(v[i]);
| ^~
train.cpp:35:47: error: expected ']' before ';' token
35 | for(int i = 0; i < m; i++) E[u[i].pb(v[i]);
| ^
| ]
train.cpp:43:31: error: 'Q' was not declared in this scope
43 | if(ok == 1 && a[i] == 1) Q.push(i), vis[i] = 1;
| ^
train.cpp:46:12: error: 'Q' was not declared in this scope
46 | while(!Q.empty()) {
| ^
train.cpp:50:6: error: 'A' was not declared in this scope
50 | A[nd] = 1;
| ^
train.cpp:62:39: error: 'A' was not declared in this scope
62 | for(int i = 0; i < n; i++) ret.pb(A[i]);
| ^