Problem
The Fibonacci sequence starts 0, 1 and each next number is the sum of the previous two: 0, 1, 1, 2, 3, 5, 8, …. F(0) = 0 and F(1) = 1.
Implement fibonacci(n).
Input
n: The position in the sequence.
Output
Return F(n).
Constraints
0 ≤ n ≤ 90
Examples
Example 1
Input:
n = 10
Expected output:
expected = 55Input:
long long n = 10;
Expected output:
long long expected = 55;Input:
long n = 10;
Expected output:
long expected = 55;Explanation
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55: F(10) = 55.
Example 2
Input:
n = 0
Expected output:
expected = 0Input:
long long n = 0;
Expected output:
long long expected = 0;Input:
long n = 0;
Expected output:
long expected = 0;Explanation
By definition F(0) = 0.
References
This challenge is adapted for CodeUtility. Follow the statement and constraints above.