Compilare: user.cpp: In function ‘int main(int, const char**)’: user.cpp:13:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] for( char ch : str1 ) { cnt1[ch] ++; } ^ user.cpp:14:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] for( char ch : str2 ) { cnt2[ch] ++; } ^ user.cpp:19:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] if( cnt2[ch] > 0 ) { ^ user.cpp:20:74: warning: array subscript has type ‘char’ [-Wchar-subscripts] while( ans.length() > 0 && ans.back() > ch && cnt1[ans.back()] - cnt2[ans.back()] > 0 ) { ^ user.cpp:20:93: warning: array subscript has type ‘char’ [-Wchar-subscripts] while( ans.length() > 0 && ans.back() > ch && cnt1[ans.back()] - cnt2[ans.back()] > 0 ) { ^ user.cpp:21:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] cnt2[ans.back()] ++; ans.pop_back(); } ^ user.cpp:22:20: warning: array subscript has type ‘char’ [-Wchar-subscripts] cnt2[ch] --; ans.push_back( ch ); } ^ user.cpp:23:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] cnt1[ch] --; } ^