bbg-FX: in-place array shuffle #splice^evict

Update: In-Place usually requires 1) splice 2) swap.

Requirement: given a list like

{1,2,3,4,  25,29,44,33,  159,139,155,150,  177,176,169,180} which describes four Persons
{id1,id2,..age1,age2, weight1,weight2,…height1,height2,..}

Write a program to output each person’s full attributes like

{1, 25, 139, 177,   2, 29, 129, 176,   3, 24, 135, 169,   4, 33, 140, 180}

Note the number of attributes (in this case 4) is an input parameter to your program. You don’t know (or care about) the name of each attribute. If you are told there are 37 attributes in each person, just output attr1 .. attr37.

Note the input and output sequence are important.

Q (Bonus question): do it in-place without creating a new collection. You can still have a small number of variables in your code.
A: one way to “cheat” is to append each output person to end of the original vector. It will double in size, so we will truncate the first half.
A: I believe I can use the “homeless/displacement” technique.
A: I now feel many in-place array reshuffle can be done in place with a single temp variable but this may not be one of them.
A: how about starting with a linked list?

https://github.com/tiger40490/repo1/blob/cpp1/cpp/array/insitu_reshuffle_attrib_bbg.cpp has ..

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