  An introduction to the application of combinatorial optimization methods to
ground state calculations of frustrated, disordered systems is given. We
discuss the interface problem in the random bond Ising ferromagnet, the random
field Ising model, the diluted antiferromagnet in an external field, the spin
glass problem, the solid-on-solid model with a disordered substrate and other
convex cost flow problems occurring in superconducting flux line lattices and
traffic flow networks. On the algorithmic side we present a concise
introduction to a number of elementary algorithms in combinatorial
optimization, in particular network flows: the shortest path algorithm, the
maximum-flow algorithms and minimum-cost-flow algorithms. We present a short
glance at the minimum weighted matching and branch-and-cut algorithms.
