1137. N-th Tribonacci Number

https://leetcode.com/problems/n-th-tribonacci-number/

Python

class Solution:
    def tribonacci(self, n: int) -> int:
        if n < 3:
            return [0, 1, 1][n]

        t1, t2, t3 = 0, 1, 1
        for i in range(3, n+1):
            trib = t1+t2+t3
            t1, t2, t3 = t2, t3, trib

        return t3