/in/foo.cc: In function 'std::string multiply(std::string, std::string)':
/in/foo.cc:29:5: error: 'vector' was not declared in this scope
   29 |     vector<int> res(m + n, 0);
      |     ^~~~~~
/in/foo.cc:4:1: note: 'std::vector' is defined in header '<vector>'; did you forget to '#include <vector>'?
    3 | #include <algorithm>
  +++ |+#include <vector>
    4 | using namespace std;
/in/foo.cc:29:12: error: expected primary-expression before 'int'
   29 |     vector<int> res(m + n, 0);
      |            ^~~
/in/foo.cc:34:29: error: 'res' was not declared in this scope
   34 |             int sum = mul + res[i + j + 1];
      |                             ^~~
/in/foo.cc:41:20: error: 'res' was not declared in this scope
   41 |     for (int num : res) {
      |                    ^~~