由文本字符及字符在文本文件中出现的频率，构造带权路径最短的最优二叉树（哈夫曼树），并依此为基础构造字符的前缀编码（哈夫曼编码）。-Frequency of text characters and characters that appear in the text file, with the right to construct the shortest path to the optimal tree (Huffman tree), and so the basic structure for the prefix character encoding (Huffman encoding).