/in/foo.cc: In function 'std::vector<int> Mul(std::vector<int>, int)':
/in/foo.cc:9:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |     while (i < a.size() || carry) {
      |            ~~^~~~~~~~~~
/in/foo.cc:10:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |         if (i < a.size()) {
      |             ~~^~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:32:13: warning: unused variable 'j' [-Wunused-variable]
   32 |         int j = 0;
      |             ^