Mergesort bottom-up

[christopheva]

[SOLVED]
Hi,
I have a question about merge sort bottom up.

Let's take the array:
13, 7, 4, 10, 3, 5

My first step would be to compare each 2 following integers:
13, 7, 4, 10, 3, 5
7, 13, 4, 10, 3, 5
7, 13, 4, 10, 3, 5
7, 13, 4, 10, 3, 5

My second step would be to compare each 4 following integers:
7, 13, 4, 10, 3, 5
4, 7, 10, 13, 3, 5

This is where I'm stuck, how can I get the last 2 integers compared?


Thx in advance!

[stevesmithx]

Why not just compare the first four with the last two?
I think there is no need for both the left and the right arrays to be of equal length
for a comparison to take place.

[MK27]

Hi,
I have a question about merge sort bottom up.

I would say: do not consider mergesort from the bottom up. If you think you're going to hit on some undiscovered optimization, you're not. So there is no point in trying to think of it that way, it will not make it any easier for you.

Once you can code a mergesort start to finish, you can decide if I am wrong...

[christopheva]

Why not just compare the first four with the last two?
I think there is no need for both the left and the right arrays to be of equal length
for a comparison to take place.

You are correct. Stupid that I didn't see it my self...

I would say: do not consider mergesort from the bottom up. If you think you're going to hit on some undiscovered optimization, you're not. So there is no point in trying to think of it that way, it will not make it any easier for you.

Once you can code a mergesort start to finish, you can decide if I am wrong...

I know, I was just wondering :-).

Thx for the replies!