UNIT-MEMORY CODES KNAPSACK PROBLEM GRAPH ORIENTATION TRELLIS CODES PUBLIC-KEY SCHEME DIGRAPH SUBDIVISION GRAPH COLORING OPTIMUM CODES COMBINATORIAL OPTIMIZATION NP-COMPLETENESS CRYPTOGRAPHIC SCHEMES PARTITION PROBLEMS ML DECODING CONVEX RECOLORING MULTIVITERBI DECODING CRYPTOSYSTEM CRYPTOGRAPHY APPROXIMATION ALGORITHMS EXACT ALGORITHMS ALGORITHMIC GAME THEORY POLYHEDRAL STUDY