answer.code: In function ‘void dfs1(int)’:
answer.code:38:13: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   38 |   for (auto [u, _] : eds[v]) {
      |             ^
answer.code: In function ‘bool dfs3(int)’:
answer.code:58:13: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   58 |   for (auto [u, w] : eds[v]) {
      |             ^
answer.code: In function ‘int main()’:
answer.code:97:3: error: ‘reverse’ was not declared in this scope
   97 |   reverse(ALL(vv));
      |   ^~~~~~~