[leetCode] 509. Fibonacci Number (Python)

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).

 

Example 1:

Input: 2
Output: 1
Explanation: F(2) = F(1) + F(0) = 1 + 0 = 1.

Example 2:

Input: 3
Output: 2
Explanation: F(3) = F(2) + F(1) = 1 + 1 = 2.

Example 3:

Input: 4
Output: 3
Explanation: F(4) = F(3) + F(2) = 2 + 1 = 3.

 

Note:

0 ≤ N ≤ 30.

 

Solution

class Solution:
    def fib(self, N: int) -> int:
        n = N
        fiboNum = 0
        
        if n == 1:
            fiboNum = 1
        elif n == 2:
            fiboNum = 1
        elif n >= 3:
            fibo = [0] * (n)
            fibo[0] = 1
            fibo[1] = 1

            for i in range(2, n):
                fibo[i] = fibo[i-1] + fibo[i-2]

            fiboNum = fibo[n-1]
            
        return fiboNum

 

SOMJANG/CODINGTEST_PRACTICE