Compilare: main.cpp: In function 'std::__cxx11::string ins(char, int, std::__cxx11::string)': main.cpp:16:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = pos; i < ans.size(); i++) ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:45:15: warning: array subscript has type 'char' [-Wchar-subscripts] freq[c] = best; ^ main.cpp:51:21: warning: array subscript has type 'char' [-Wchar-subscripts] while(freq[c]) ^ main.cpp:61:23: warning: array subscript has type 'char' [-Wchar-subscripts] freq[c]--; ^