1137. N-th Tribonacci Number

import numpy as np


class Solution:
    def tribonacci(self, n: int) -> int:
        if n == 0:
            return 0
        if n < 3:
            return 1
        factor = np.mat([(1, 1, 0), (1, 0, 1), (1, 0, 0)], np.dtype("O"))
        res = np.mat([(1, 1, 0)], np.dtype("O"))
        n -= 3
        while n:
            if n & 1:
                res *= factor
            factor *= factor
            n >>= 1
        return res.sum()