Quantum machine learning is the synergy between quantum computing resources and machine learning methods. In particular, quantum machine learning refers to quantum algorithms promising to compute some machine learning methods and optimization problems (polynomially) faster than conventional algorithms. Quantum algorithms for computing any problems are algorithms using a quantum computer. This work (I) identifies intractable real-world problems of practical significance which can be computed efficiently on a quantum computer, (II) provides an encoding strategy of real-world, large scale problems in a small-scale quantum computer, and (III) invents so-called hybrid classical-quantum (HPC+nQC) learning networks and analyses their performance i...