Compilare: user.cpp: In function ‘int main()’: user.cpp:17:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 1; i <= N; ++i ) ^ user.cpp:20:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 2; i < N; ++i ) ^ user.cpp:22:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int j = i + 1; j <= N; ++j ) ^ user.cpp:27:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int k = 0; k < H[Gate].size(); ++k ) ^ user.cpp:40:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int k = 0; k < H[Gate].size(); ++k ) ^