Compilare: user.cpp: In function ‘void backtr(long long int)’: user.cpp:49:25: 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:89:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0 ; i < rez.size() ; i++ ) ^ user.cpp:94:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0 ; i < sol.size() ; i++ ) ^