模拟LZ78压缩算法的过程，算法有文字描述部分，按步执行-LZ78 compression algorithm simulation process, the algorithm has the text descr iption, step by step execution

Lempel–Ziv–Welch (LZW) is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. It was published by Welch in 1984 as an improved implementation of the LZ78 algorithm published by Lempel and Ziv in 1978