比较两个表的子串，只返回差值

def build_partial_match_table(pattern):
    table = [0] * len(pattern)
    i, j = 1, 0
    while i < len(pattern):
        if pattern[i] == pattern[j]:
            j += 1
            table[i] = j
            i += 1
        else:
            if j > 0:
                j = table[j-1]
            else:
                table[i] = 0
                i += 1
    return table

def compare_tables(table1, table2):
    pattern = ''.join(table1)
    text = ''.join(table2)
    table = build_partial_match_table(pattern)
    matches = []
    i, j = 0, 0
    while i < len(text):
        if text[i] == pattern[j]:
            i += 1
            j += 1
            if j == len(pattern):
                matches.append(text[i-j:i])
                j = table[j-1]
        else:
            if j > 0:
                j = table[j-1]
            else:
                i += 1
    return matches

# 示例用法
table1 = ['abc', 'def', 'ghi']
table2 = ['abc', 'xyz', 'def', 'uvw', 'ghi']
differences = compare_tables(table1, table2)
print(differences)