leetcode 1137

 1 class Solution:
 2     def tribonacci(self, n: int) -> int:
 3         if n == 0:
 4             return 0
 5         elif n == 1:
 6             return 1
 7         elif n == 2:
 8             return 1
 9         else:
10             dp = [0] * (n + 1)
11             dp[1] = 1
12             dp[2] = 1
13             for i in range(3,n+1):
14                 dp[i] = dp[i-1] + dp[i-2] + dp[i-3]
15             return dp[n]

posted on 2019-07-28 10:43 Sempron2800+ 阅读(93) 评论(0) 编辑收藏举报