LESSON 257 OF 348 · RECURSION

Recursive Fibonacci in Scala

Practice O(2ⁿ)

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.

Write a recursive function that given n, returns F(n).

Example 1:

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

Example 2:

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

Example 3:

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

Constraints:

0 <= n <= 30

Note:

Don't worry about the time and space complexities of your algorithm.

Hints:

Inside the function, we should first check the base case: if n is less than 2, then we should return n.

If n >= 2, since F(n) = F(n - 1) + F(n - 2), we should return fibonacci(n - 1) + fibonacci(n - 2).

STEP 1 OF 2

Guided

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