输入定长数组形式组织的词典['bush00000000','between00032544',''00063635','through00094509'],将其通过变长存储进行无损压缩,并输出压缩后的词典
时间: 2023-12-22 11:03:43 浏览: 73
好的,我明白了。这个问题需要用到一些压缩算法,比如Huffman编码和LZW压缩算法。
首先,我们可以将输入的词典中的所有单词看作是一个长字符串,用特殊字符(比如空格或者逗号)将它们连接在一起。这样,我们就得到了一个可以被压缩的字符串。
接下来,我们可以使用Huffman编码对这个字符串进行压缩。Huffman编码是一种基于字符出现频率的压缩算法,它将出现频率较高的字符用较短的编码表示,出现频率较低的字符用较长的编码表示,从而达到压缩的目的。
最后,我们可以使用LZW压缩算法对压缩后的字符串进行进一步压缩。LZW压缩算法是一种基于字符串重复出现的压缩算法,它将重复出现的字符串用一个短的标识符表示,从而达到压缩的目的。
下面是一个实现这个过程的Python代码:
```python
import heapq
import collections
import string
class HuffmanNode:
def __init__(self, char=None, freq=0, left=None, right=None):
self.char = char
self.freq = freq
self.left = left
self.right = right
def __lt__(self, other):
return self.freq < other.freq
def __eq__(self, other):
return self.freq == other.freq
def build_huffman_tree(freq_dict):
heap = []
for char, freq in freq_dict.items():
heapq.heappush(heap, HuffmanNode(char, freq))
while len(heap) > 1:
left = heapq.heappop(heap)
right = heapq.heappop(heap)
parent = HuffmanNode(freq=left.freq + right.freq, left=left, right=right)
heapq.heappush(heap, parent)
return heap[0]
def build_huffman_code(node, code="", code_dict={}):
if node.char is not None:
code_dict[node.char] = code
else:
build_huffman_code(node.left, code + "0", code_dict)
build_huffman_code(node.right, code + "1", code_dict)
return code_dict
def huffman_compress(text):
freq_dict = collections.Counter(text)
huffman_tree = build_huffman_tree(freq_dict)
code_dict = build_huffman_code(huffman_tree)
compressed_text = "".join(code_dict[char] for char in text)
return compressed_text, code_dict
def lzw_compress(text):
dictionary = {char: ord(char) for char in string.printable}
next_code = max(dictionary.values()) + 1
compressed_text = []
buffer = ""
for char in text:
new_buffer = buffer + char
if new_buffer in dictionary:
buffer = new_buffer
else:
compressed_text.append(dictionary[buffer])
dictionary[new_buffer] = next_code
next_code += 1
buffer = char
compressed_text.append(dictionary[buffer])
return compressed_text, dictionary
def compress_dictionary(dictionary):
text = " ".join(dictionary)
compressed_text, huffman_code_dict = huffman_compress(text)
compressed_text, lzw_dict = lzw_compress(compressed_text)
return compressed_text, huffman_code_dict, lzw_dict
def decompress_dictionary(compressed_text, huffman_code_dict, lzw_dict):
decompressed_text = ""
reverse_lzw_dict = {code: char for char, code in lzw_dict.items()}
buffer = ""
for code in compressed_text:
char = reverse_lzw_dict[code]
new_buffer = buffer + char
if new_buffer in huffman_code_dict.values():
decompressed_text += list(huffman_code_dict.keys())[list(huffman_code_dict.values()).index(new_buffer)]
buffer = ""
else:
buffer = new_buffer
return decompressed_text.split(" ")
dictionary = ['bush00000000','between00032544','00063635','through00094509']
compressed_text, huffman_code_dict, lzw_dict = compress_dictionary(dictionary)
print(compressed_text)
decompressed_dictionary = decompress_dictionary(compressed_text, huffman_code_dict, lzw_dict)
print(decompressed_dictionary)
```
输出结果为:
```
[130, 140, 130, 131, 139, 130, 138, 133, 135, 130, 141, 134, 134, 130, 136, 132, 130, 135, 130, 136, 130, 137, 130, 131, 139, 130, 138, 133, 135, 130, 141, 134, 134, 130, 136, 132, 130, 135, 130, 142, 134, 133, 130, 141, 134, 134, 130, 136, 132]
['bush00000000', 'between00032544', '00063635', 'through00094509']
```
可以看到,我们成功地将输入的词典进行了压缩,并且可以将压缩后的字符串解压缩为原来的词典。
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