'Input: \'k\', \'lamda\' being the two class representatives to be merged.
Merge two classes with representatives ``k`` and ``lamda``, described
on Pg. 157 [1] (for pseudocode), start by putting ``p[k] = lamda``.
It is more efficient to choose the new representative from the larger
of the two classes being merged, i.e larger among ``k`` and ``lamda``.
procedure ``merge`` performs the merging operation, adds the deleted
class representative to the queue ``q``.
Notes
Pg. 86-87 [1] contains a description of this method.
See Also
coincidence, rep'

def merge(self, k, lamda, q):

    p = self.p
    phi = self.rep(k)
    psi = self.rep(lamda)
    if (phi != psi):
        mu = min(phi, psi)
        v = max(phi, psi)
        p[v] = mu
        q.append(v)
