Introduction - If you have any usage issues, please Google them yourself
The program is divided into the main achievements, encoding, decoding three chunks. Contribution can be divided into three sub-processes: frequency statistics to create a single linked list of leaf nodes, leaf nodes connected into a tree. The creation of a single linked list: the establishment of the existing leaf node for each character, according to the weight increment ordered into a single list, and then leaves the character pointer (whose role will be mentioned later) point to the node.