CODEWITHSUNDEEP
python
StevenJerrard
StevenJerrard

Reputation: 11

Python coding using collatz conjecture

I am new at coding and i am trying to do a collatz conjecture.

I think i already made it by i cant code a way to count how much "steps" it takes to the 1.

This is the code i already did.

n = int(input("Enter a number!"))

def lothar(n):
    print(n)
    if n == 1:
        return i
    if n % 2 == 0:
        n = n / 2
    else:
        n = ((n*3) + 1) 
    return lothar(n)

print(lothar(n))

I want to count using a while structure.

For example: in number 4 , it takes 3 steps.
4
2
1.

Upvotes: 0

Views: 302

Answers (2)

Robson
Robson

Reputation: 2032

There's a few ways to count the steps, but I've gone with removing the recursion and using a loop instead:

n = int(input("Enter a number: "))

def lothar(n):
    steps = [n]
    while n > 1:
        if n % 2 == 0:
            n = n // 2
        else:
            n = ((n*3) + 1) 
        steps.append(n)
    return steps

sequence = lothar(n)
print(sequence)
print(str(len(sequence)-1) + " step(s)")

That will return the sequence, which then means we can display the sequence and also output the amount of steps (i.e. the length of the sequence minus one).

For example:

Enter a number: 9
[9, 28, 14, 7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1]
19 step(s)

Upvotes: 1

Peter
Peter

Reputation: 110

Put the while loop into the function, and give a count variable for counting.

n = int(input("Enter a number!"))

count = 1

def lothar(n,count):         
    while n != 1:     
        if n % 2 == 0:                
            count += 1
            n = n / 2             
        else:    
            count += 1
            n = ((n*3) + 1)    
    return count

print(lothar(n,count))

Because the result you want is to include 4, count will be added one more time, but if you want to count the number of loops, you should set count to 0 for calculation.

Upvotes: 0

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