Recursion: Fibonacci Numbers

Problem Statement :

The Fibonacci Sequence

The Fibonacci sequence appears in nature all around us, in the arrangement of seeds in a sunflower and the spiral of a nautilus for example.

The Fibonacci sequence begins with fibonacci(0) = 0 and  fibonnaci(1) = 1 as its first and second terms. After these first two elements, each subsequent element is equal to the sum of the previous two elements.


fibonacci(0) = 0
fibonacci(1) = 1
fibonacci(n) =  fibonacci( n - 1 ) + fibonacci( n - 2 )

Function Description

Complete the recursive function fibonacci in the editor below.

fibonacci has the following parameter(s):

int n: the index of the sequence to return

- int: the nth element in the Fibonacci sequence

Input Format

The integer n.


0   <=   n   <=  30

Solution :


                            Solution in C :

In   C :

    if(n == 0)
        return 0;
    else if(n == 1)
        return 1;
        return fibonacci(n-1)+fibonacci(n-2);

                        Solution in C++ :

In   C ++   :

    // Complete the function.
            return 0;
    else if(n==1)
            return 1;
        return (fibonacci(n-1)+fibonacci(n-2));

                        Solution in Java :

In   Java   :

        // Complete the function.
        if(n == 0) return 0;
        if(n == 1) return 1;
        return fibonacci(n - 1) + fibonacci(n - 2);

                        Solution in Python : 
In   Python3  :

cache = {0:0, 1:1}

def fibonacci(n):
        return cache[n]
    except KeyError:
        cache[n] = fibonacci(n - 1) + fibonacci(n - 2)
        return cache[n]

n = int(input())

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