INT102-Horspool Algorithm

def horsepool(S: str, P: str) -> tuple:
    n, m, M = len(S), len(P), 26
    shift_table = [m for _ in range(M)]
    for i in range(m - 1):
        shift_table[ord(P[i]) - ord('A')] = m - i - 1
    pos, ans, flag = 0, [], False

    while pos <= (n - m):
        j = m - 1
        while j >= 0 and S[pos + j] == P[j]:
            j -= 1
        if j == -1:
            flag = True
            ans.append(pos)
            pos += m
        else:
            pos += shift_table[ord(S[pos + m - 1]) - ord('A')]
    if not flag:
        print("Not find")
    return flag, ans, shift_table


if __name__ == '__main__':
    S = "AGCAATGAA"
    P = "ATGAA"
    flag, pos, table = horsepool(S, P)
    print(flag)
    print(pos)
    print(table)