Python Program for Fibonacci numbers

In this article, we will learn about the solution and approach to solve the given problem statement.

Problem statement −Our task to compute the nth Fibonacci number.

The sequence Fn of Fibonacci numbers is given by the recurrence relation given below

Fn = Fn-1 + Fn-2

with seed values (standard)

F0 = 0 and F1 = 1.

We have two possible solutions to the problem

• Recursive approach
• Dynamic approach

Approach 1 −Recursive Approach

Example

 Live Demo

#recursive approach def Fibonacci(n):    if n<0:       print("Fibbonacci can't be computed")    # First Fibonacci number    elif n==1:       return 0    # Second Fibonacci number    elif n==2:       return 1    else:       return Fibonacci(n-1)+Fibonacci(n-2) # main n=10 print(Fibonacci(n))

Output

34

All the variables are declared in global scope as shown in the image below

Approach 2 −Dynamic Approach

Example

 Live Demo

#dynamic approach Fib_Array = [0,1] def fibonacci(n):    if n<0:       print("Fibbonacci can't be computed")    elif n<=len(Fib_Array):       return Fib_Array[n-1]    else:       temp = fibonacci(n-1)+fibonacci(n-2)       Fib_Array.append(temp)       return temp # Driver Program n=10 print(fibonacci(n))

Output

34

All the variables are declared in global scope as shown in the image below

Conclusion

In this article, we learnt about the approach to compute Fibonacci numbers