哈夫曼树的建立。（可求哈弗曼编码）

1.在已有的字符和权中，用select函数选出其中权最小的两个字符；

2.在哈夫曼树的存储结构中，用这两个字符建立与其parent的关系；

3.从n+1到2*n-1依次算出各字符的parent，可得Huffman树；-Huffman tree establishment. (Rectifiable Huffman coding)

1. In the existing character and the right, with the right to elect one of the smallest function　two characters

2. In the storage structure Huffman tree, the characters build relationships with both of its parent

3. Dao　n+ 1 2* n-1 sequentially calculates the parent of each character can be obtained Huffman tree