用python写个KMP算法

您好，我是C知道，可以回答您的问题。KMP算法是一种字符串匹配算法，可以在一个文本串S内查找一个模式串P的出现位置。以下是用Python实现KMP算法的代码：

def kmp_search(text, pattern):
    n = len(text)
    m = len(pattern)
    if m == :
        return 
    next = get_next(pattern)
    j = 
    for i in range(n):
        while j >  and text[i] != pattern[j]:
            j = next[j - 1]
        if text[i] == pattern[j]:
            j += 1
        if j == m:
            return i - m + 1
    return -1

def get_next(pattern):
    m = len(pattern)
    next = [] * m
    j = 
    for i in range(1, m):
        while j >  and pattern[i] != pattern[j]:
            j = next[j - 1]
        if pattern[i] == pattern[j]:
            j += 1
        next[i] = j
    return next

希望能帮到您。