/in/foo.cc: In function 'std::__cxx11::string solve(std::__cxx11::string&, int)':
/in/foo.cc:12:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < str.size(); ++i) {
                     ~~^~~~~~~~~~~~
/in/foo.cc:15:29: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
         num[i % m] = (a ^ b == 0) ? '0' : '1';
                           ~~^~~~
/in/foo.cc: In function 'std::__cxx11::string doReverse(std::__cxx11::string&)':
/in/foo.cc:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < s.size(); ++i) {
                     ~~^~~~~~~~~~
/in/foo.cc: In function 'int cnt(std::__cxx11::string&, char)':
/in/foo.cc:29:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < s.size(); ++i) {
                     ~~^~~~~~~~~~
/in/foo.cc: In function 'std::__cxx11::string ifReverse(std::__cxx11::string&)':
/in/foo.cc:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if ((c & 1) || (c == str.size())) {
                     ~~^~~~~~~~~~~~~