BF算法与KMP算法的python实现

最近在学习子串排序算法，在此记录下实现方式

def bf(string1, string2):
    """
    bf
    :param string1:
    :param string2:
    :return:
    """
    x, y = 0, 0
    while x < len(string1) and y < len(string2):
        if string1[x] == string2[y]:
            x += 1
            y += 1
            continue
        x = x - y + 1
        y = 0
    if y >= len(string2):
        return x - len(string2)
    return 0

def get_next_list(substring):
    """
    获取next列表
    :param substring:
    :return:
    """
    next_list = [0] * len(substring)
    x, y = 0, 1
    while y < len(substring):
        if substring[x] == substring[y]:
            x += 1
            next_list[y] = x
            y += 1
        else:
            if x == 0:
                next_list[y] = 0
                y += 1
                continue
            x = next_list[x - 1]
    return next_list


def kmp(string1, string2):
    """
    kmp
    :param string1:
    :param string2:
    :return:
    """
    x, y = 0, 0
    next_list = get_next_list(string2)
    while x < len(string1) and y < len(string2):
        if string1[x] == string2[y]:
            x += 1
            y += 1
        else:
            if y == 0:
                x += 1
                continue
            y = next_list[y]

    if y >= len(string2):
        return x - len(string2)
    return 0


if __name__ == '__main__':
    res_kmp = kmp("sdadddababab", "dabab")
    print(res_kmp)