answer.code:189:5: error: expected unqualified-id before ‘if’
  189 |     if (res)
      |     ^~
answer.code:193:5: error: expected unqualified-id before ‘for’
  193 |     for (auto [p, q] : fix_ans) {
      |     ^~~
In file included from /usr/include/c++/11/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:33,
                 from answer.code:1:
answer.code:196:5: error: expected unqualified-id before ‘static_cast’
  196 |     assert(size(fix_ans) + flow.flow() == n);
      |     ^~~~~~
answer.code:196:5: error: expected ‘)’ before ‘static_cast’
answer.code:199:15: error: ‘flow’ was not declared in this scope
  199 |     auto &E = flow.edges;
      |               ^~~~
answer.code:200:5: error: expected unqualified-id before ‘for’
  200 |     for (int i = 0 ; i < size(E) ; ++ i) {
      |     ^~~
answer.code:200:22: error: ‘i’ does not name a type
  200 |     for (int i = 0 ; i < size(E) ; ++ i) {
      |                      ^
answer.code:200:36: error: expected unqualified-id before ‘++’ token
  200 |     for (int i = 0 ; i < size(E) ; ++ i) {
      |                                    ^~
In file included from /usr/include/c++/11/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/11/bits/stdc++.h:33,
                 from answer.code:1:
answer.code:213:5: error: expected unqualified-id before ‘static_cast’
  213 |     assert(strlen(ans) == n);
      |     ^~~~~~
answer.code:213:5: error: expected ‘)’ before ‘static_cast’
answer.code:214:5: error: ‘ans’ does not name a type
  214 |     ans[n] = '\0';
      |     ^~~
answer.code:215:5: error: ‘cout’ does not name a type
  215 |     cout << ans << '\n';
      |     ^~~~
answer.code:220:1: error: expected declaration before ‘}’ token
  220 | }
      | ^