一、 参考书《数据压缩导论（第4版）》 Page 121
7，8
解：
C(a)=1,C(b)=2,C(r)=3,C(t)=4;
解码过程：
|
序列 |
输出 |
|
<0,0,3> |
r |
|
<0,0,1> |
ra |
|
<0,0,4> |
rat |
|
<2,8,2> |
ratatatatatb |
|
<3,1,2> |
ratatatatatbab |
|
<0,0,3> |
ratatatatatbabr |
|
<6,4,4,> |
ratatatatatbabratbat |
|
<9,5,4> |
ratatatatatbabratbatbabrat
|
编码过程：输入序列：ratatatatat a rat at a rat
接下来继续编码：
| 输入 | 输出 |
| ||ratatatatat a rat at a rat | <0, 0, 3> |
| |r|atatatatat a rat at a rat | <0, 0, 1> |
| |ra|tatatatat a rat at a rat | <0, 0, 4> |
| |rat|atatatat a rat at a rat | <2, 8, 2> |
| ra|tatatatat |a rat at a rat | <3, 1, 2> |
| rata|tatatat a |rat at a rat | <0, 0, 3> |
| ratat|atatat a r|at at a rat | <6, 4, 4> |
| ratatatata|t a rat at| a rat | <9, 5, 4> |
根据这2个过程得出：编码输出的三元组与解码输入的三元组完全一样。
8.给定一下初始词典和接收序列，构建一个LZW词典，并对所发送的序列进行编码。
接收序列：4,5,3,1,2,8,2,7,9,7,4
初始字典：
| 索引 | 项 |
| 1 | S |
| 2 | |
| 3 | I |
| 4 | T |
| 5 | H |
解：
(1)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _(空格) |
| 3 | I |
| 4 | T |
| 5 | H |
该数解码的序列为：T
(2)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
该数解码的序列为：TH
(3)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _(空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
该数解码的序列为：THI
(4)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
该数解码的序列为：THIS
(5)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
| 8 | IS |
该数解码的序列为：THIS_
(6)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
| 8 | IS |
| 9 | S_ |
该数解码的序列为：THIS IS
(7)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
| 8 | IS |
| 9 | S_ |
| 10 | _I |
该数解码的序列为：THIS IS_
(8)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
| 8 | IS |
| 9 | S_ |
| 10 | _I |
| 11 | IS_ |
该数解码的序列为：THIS IS HI
(9)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
| 8 | IS |
| 9 | S_ |
| 10 | _I |
| 11 | IS_ |
| 12 | _H |
该数解码的序列为：THIS IS HIS_
(10)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
| 8 | IS |
| 9 | S_ |
| 10 | _I |
| 11 | IS_ |
| 12 | _H |
| 13 | HIS |
该数解码的序列为：THIS IS HIS HI
(11)输入4,5,3,1,2,8,2,7,9,7,4
| 索引 | 条目 |
| 1 | S |
| 2 | _ (空格) |
| 3 | I |
| 4 | T |
| 5 | H |
| 6 | TH |
| 7 | HI |
| 8 | IS |
| 9 | S_ |
| 10 | _I |
| 11 | IS_ |
| 12 | _H |
| 13 | HIS |
| 14 | S_H |
该数解码的序列为：THIS IS HIS HIT