509. Fibonacci Number
The Fibonacci numbers, commonly denoted F(n)
form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0
and 1
. That is,
F(0) = 0, F(1) = 1 F(N) = F(N - 1) + F(N - 2), for N > 1.
Given N
, calculate F(N)
.
斐波那契数列,按照递推公式来就行
class Solution(object): def fib(self, N): """ :type N: int :rtype: int """ fa = [0, 1] for i in range(2, N + 1, 1): fa.append(fa[i - 1] + fa[i -2]) return fa[N]