Suppose that we have an algorithm to solve vertex cover—for any graph and any integer m it determines whether there exists a vertex cover of cardinality at most m or reports that none exists. Show how...

Suppose that we have an algorithm to solve vertex cover—for any graph and any integer m it determines whether there exists a vertex cover of cardinality at most m or reports that none exists. Show how to use such an algorithm to solve the optimization version of the problem—given any graph, find a vertex cover of minimal cardinality.