We construct the Fock space representations of classical quantum affine
algebras using combinatorics of Young walls. We also show that the crystal
graphs of the Fock space representations can be realized as the abstract
crystal consisting of proper Young walls. Finally, we give a generalized
version of Lascoux-Leclerc-Thibon algorithm for computing the global bases of
the basic representations of classical quantum affine algebras.Comment: 70 page