Shell sort works the same no matter what gaps you use.
The only thing that changes is which gaps you make between elements.
Think of it like this:
- Shell sort = “insertion sort, but you start by jumping far.”
- The gap sequence = “how big your jumps are before you switch to smaller jumps.”
Your code uses:
n/2 → n/4 → n/8 →... → 1
Ciura or Sedgewick just replace those numbers with better jump sizes.
So instead of letting Java calculate them in a loop, you simply:
Make a list of gaps (Ciura: 701, 301, 132 … 1)
Start from the biggest one that fits your array
Run the same sorting logic for each gap
Nothing else changes.
You are not rewriting the algorithm. you are only changing the list of gap numbers. That is all.
In other words: Shell sort = same engine, different gear ratios.