常见应用中是否有随机访问压缩？

在一些常见的应用中，如图像和视频压缩，我们需要能够随机访问压缩数据以快速读取或写入指定的数据部分。一个常见的解决方法是使用基于哈夫曼编码和符号移位的压缩算法，如JPEG和H.264。这些算法可以将压缩数据组织成多个块，每个块都可以被独立地解码和访问。

以下是一个基于Python的哈夫曼编码压缩和解压缩示例：

import heapq
import sys


def compress(text):
    # 构建字符频率字典
    freq_dict = {}
    for char in text:
        if char in freq_dict:
            freq_dict[char] += 1
        else:
            freq_dict[char] = 1

    # 构建哈夫曼树
    heap = [[weight, [symbol, ""]] for symbol, weight in freq_dict.items()]
    heapq.heapify(heap)
    while len(heap) > 1:
        lo = heapq.heappop(heap)
        hi = heapq.heappop(heap)
        for pair in lo[1:]:
            pair[1] = '0' + pair[1]
        for pair in hi[1:]:
            pair[1] = '1' + pair[1]
        heapq.heappush(heap, [lo[0] + hi[0]] + lo[1:] + hi[1:])

    # 构建字符-编码字典
    huffman_dict = {char: code for char, code in heap[0][1:]}

    # 对文本进行编码
    result = ""
    for char in text:
        result += huffman_dict[char]

    return result, huffman_dict


def decompress(encoded_text, huffman_dict):
    # 反转哈夫曼字典
    inverted_dict = {v: k for k, v in huffman_dict.items()}

    # 解码文本
    result = ""
    code = ""
    for bit in encoded_text:
        code += bit
        if code in inverted_dict:
            result += inverted_dict[code]
            code = ""

    return result


# 示例用法
text = "hello world"
compressed_text, huffman_dict = compress(text)
print("压缩前的文本：", text)
print("压缩后的文本：", compressed_text)
print("哈夫曼字典：", huffman_dict)
decompressed_text = decompress(compressed_text, huffman_dict)
print("解压缩后的文本：", decompressed_text)