1. A machine system for solving an optimization or constraint satisfaction problem, comprising: a digital computer, said digital computer comprising: one or more memory devices for storing weak and strong problem solving methods, decision variables having decision variable values, and heuristics; first means for utilizing said weak and strong problem solving methods to manipulate the decision variable values to find at least a best balanced solution to the problem; and second means for utilizing said heuristics to dynamically alternate between said weak and strong problem solving methods.