train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:8:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
8 | for (int i = 0; i < u.size(); i++) {
| ~~^~~~~~~~~~
train.cpp: In lambda function:
train.cpp:15:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
15 | for (int i = 0; i < s.size(); i++) {
| ~~^~~~~~~~~~
train.cpp:19:27: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'long unsigned int' [-Wsign-compare]
19 | if (!vis[v] && out[v] >= (a[v] ? 1 : ad[v].size())) {