/in/foo.cc: In function 'll euler_phi(ll)':
/in/foo.cc:107:16: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17' [-Wc++17-extensions]
  107 |     for (auto& [p, cnt] : factors) {
      |                ^
/in/foo.cc: In function 'std::vector<long long int> get_distinct_prime_factors(ll)':
/in/foo.cc:117:16: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17' [-Wc++17-extensions]
  117 |     for (auto& [p, cnt] : factors) {
      |                ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:202:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<Interval>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  202 |         for (int j = start; j < stack.size(); ++j) {
      |                             ~~^~~~~~~~~~~~~~