Compilare: user.cpp: In function ‘int main()’: user.cpp:36:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0 ; i < P[v[m-1]].size() ; ++i ) ^ user.cpp:40:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0 ; j < P[v[i]].size() ; ++j ) ^ user.cpp:51:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0 ; j < P[v[0]].size() ; ++j ) ^