I have read that Flow network is a directed graph, with no self loops and there is no reverse edges and non negative capacity. However in Residual network, we allow the reverse edges so we can cancel(subtract) some units from the flow. My question is why there is no reversed edges in flow networ...

The Hamiltonian cycle problem asks if a given graph contains a Hamiltonian cycle. The Hamiltonian cycle problem belongs to the class of NP-complete problems. However, for some special classes of graphs, the problem can be solved in polynomial time, for example, 4-connected planar graphs. A graph...