Compilare: main.cpp: In function 'int main()': main.cpp:69:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j=0;j<s[i].size();j++ ) ~^~~~~~~~~~~~ main.cpp:71:32: warning: narrowing conversion of '((((std::__cxx11::basic_string<char>::size_type)(2 * j)) - s[i].std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size<char, std::char_traits<char>, std::allocator<char> >()) + 1ul)' from 'std::__cxx11::basic_string<char>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] q.push({2*j-s[i].size()+1,s[i].size()}); ~~~~~~~~~~~~~~~^~ main.cpp:71:44: warning: narrowing conversion of 's[i].std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size<char, std::char_traits<char>, std::allocator<char> >()' from 'std::__cxx11::basic_string<char>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] q.push({2*j-s[i].size()+1,s[i].size()}); ~~~~~~~~~^~