1137. N-th Tribonacci Number

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

题目介绍:

Tribonacci的规则如下:
T0 = 0
T1 = 1
T2 = 1
Tn + 3 = Tn + Tn+1 + Tn+2

请回传Tn的结果

example

解法:

其实就是费氏数列的改版，原本的前两项相加变成前三项相加

程序码

class Solution:
    def tribonacci(self, n: int) -> int:
        
        Tri = [0, 1, 1]
        
        if n < 3:
            return Tri[n]
        else:
            for i in range(3, n+1):
                Tri.append(Tri[i-3] + Tri[i-2] + Tri[i-1])
        
        return Tri[-1]

闲聊

差点睡过头赶不上