编写 Python 程序实现对文本文件做 LZ77 编码，编码后的文件以二进制 文件的形式存储；  编写 Python 程序实现对 LZ77 压缩后的二进制文件解码，恢复出原始的 文本文件并保存；  在 Python 程序中，分别统计出编码和解码所需要的时间（单位秒），并 打印出来。

以下是 Python 实现对文本文件做 LZ77 编码并保存为二进制文件的代码示例：

import time

def lz77_compress(uncompressed, window_size=12, look_ahead_buffer_size=5):
    compressed = bytearray()
    pos = 0
    while pos < len(uncompressed):
        max_match_length = 0
        max_match_distance = 0
        for dist in range(1, window_size + 1):
            start_pos = max(0, pos - dist)
            match_length = 0
            while pos + match_length < len(uncompressed) and uncompressed[start_pos + match_length] == uncompressed[pos + match_length] and match_length < look_ahead_buffer_size:
                match_length += 1
            if match_length > max_match_length:
                max_match_length = match_length
                max_match_distance = dist
            if match_length == look_ahead_buffer_size:
                break
        if max_match_length > 0:
            compressed.append(max_match_distance // 256)
            compressed.append(max_match_distance % 256)
            compressed.append(max_match_length)
            pos += max_match_length
        else:
            compressed.append(0)
            compressed.append(0)
            compressed.append(uncompressed[pos])
            pos += 1
    return compressed

def lz77_decompress(compressed):
    decompressed = bytearray()
    pos = 0
    while pos < len(compressed):
        dist = compressed[pos] * 256 + compressed[pos + 1]
        length = compressed[pos + 2]
        if dist == 0:
            decompressed.append(length)
            pos += 3
        else:
            start_pos = len(decompressed) - dist
            for i in range(length):
                decompressed.append(decompressed[start_pos + i])
            pos += 3
    return decompressed

# 读取文件并进行 LZ77 编码
start_time = time.time()
with open('input.txt', 'r') as f:
    uncompressed = f.read()
compressed = lz77_compress(uncompressed.encode())
with open('compressed.bin', 'wb') as f:
    f.write(compressed)
end_time = time.time()
print(f"LZ77 编码耗时：{end_time - start_time:.3f} 秒")

# 读取二进制文件并进行 LZ77 解码
start_time = time.time()
with open('compressed.bin', 'rb') as f:
    compressed = f.read()
decompressed = lz77_decompress(compressed)
with open('output.txt', 'w') as f:
    f.write(decompressed.decode())
end_time = time.time()
print(f"LZ77 解码耗时：{end_time - start_time:.3f} 秒")

以上代码中，`lz77_compress` 函数和 `lz77_decompress` 函数的实现与前面的示例类似，不同之处在于压缩结果和解压缩输入都是字节数组，而不是字符串。

程序中使用了 Python 的 `time` 模块来统计编码和解码所需要的时间。程序首先读取原始文本文件，对其进行 LZ77 编码并将结果保存为二进制文件。然后程序再次读取二进制文件，进行 LZ77 解码并将结果保存为文本文件。最后程序打印出编码和解码所需要的时间，单位为秒。