HenrikLovold / FastCollatz

Can you make it fast?

FastCollatz

Can you make it fast?

What is Collatz' conjecture?

See Wikipedia.

What is the challenge?

Compute the length of all Collatz paths for numbers 2 to N as fast as possible. Some example lengths:

Number	Path length
2	1
3	7
4	2
5	5
6	8

If you need an example program, have a look at this file.

Basic Collatz function

collatz(x):
  if x % 2 == 0:
    return x / 2
  else:
    return x*3 + 1

Rules

• Calculate all Collatz paths for 2 to N
• Your program's first argument must be N

For testing purposes, run $N=1*10^7$, as this is what we're benchmarking.