Compilare: user.cpp: In function ‘void biconex(int, int)’: user.cpp:50:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0 ; i<a[x].size() ; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:87:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0 ; i<sol.size() ; ++i) ^ user.cpp:89:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0 ; j<sol[i].size() ; ++j) ^