Compilare: user.cpp: In function ‘void backtr(long long int)’: user.cpp:42:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0 ; i < v.size() ; i++ ) ^ user.cpp: In function ‘int main()’: user.cpp:82:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0 ; i < rez.size() ; i++ ) ^ user.cpp:86:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0 ; i < sol.size() ; i++ ) ^