set intervals with starts and ends in two arrays

I know this should be quite an easy answer, but I cannot find the solution: I have two arrays one marks the beginning of the intervals the other sets the ends. so:

starts = [ 1 20 30 40];
ends = [3 22 34 41];

with the ends always ending before the next start. I would like to get an array intervals which should appear either:

intervals = [1 2 3 20 21 22 30 31 32 33 34 40 41];

or:

intervals = [1 2 3; 20 21 22; 30 31 32 33 34; 40 41];

this sounds so dumb to me that I cannot find a way...anyway, I hope somebody can easily help me thanks.

Also, I need to AVOID FOR CYCLES TO DO IT.

[Matt J]

Also, I need to AVOID FOR CYCLES TO DO IT.

Why?

[gabriele fadanelli]

I don't really know, but the solution to the problem should be given without using a for cycle, it is mandatory, not my fault.

[gabriele fadanelli]

I thought it was easy to do it with

starts : ends 

or

starts':ends'

but none of them works

Answer 1

[Matt J]

Because it's homework, I've left some blanks for you to fill in.

starts = [ 1 20 30 40];
ends = [3 22 34 41];

D=ends-starts;

M=______;
N=numel(starts);

e=(0:M).';
map=______

map = 5×4 logical array
   1   1   1   1
   1   1   1   1
   1   1   1   0
   0   0   1   0
   0   0   1   0

result=double(map).*e(:)+starts;

result(map).'

ans = 1×13

1 2 3 20 21 22 30 31 32 33 34 40 41