Compilare: main.cpp: In function 'int main()': main.cpp:21:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 21 | for(ij=0;ij<a.size();++ij){ | ~~^~~~~~~~~ main.cpp:30:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 30 | if(maxfr>=a.size()/2+1){ | ~~~~~^~~~~~~~~~~~~~ main.cpp:33:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 33 | for(int i=0;i<a.size();++i){ | ~^~~~~~~~~ main.cpp:41:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 41 | if(maxfr>=(a.size()-i)/2+1){ | ~~~~~^~~~~~~~~~~~~~~~~~ main.cpp:45:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 45 | if(maxfr==(a.size()-i)/2 && (a.size()-i)%2==0){ | ~~~~~^~~~~~~~~~~~~~~~ main.cpp:69:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 69 | for(int i=0;i<ans.size();++i){ | ~^~~~~~~~~~~ main.cpp:48:18: warning: 'cara' may be used uninitialized [-Wmaybe-uninitialized] 48 | --fr[cara-'a']; | ^~~~ main.cpp:20:14: note: 'cara' was declared here 20 | char cara; | ^~~~