QuickSort on ranges

jerome jegaultier at gmail.com
Sat Sep 12 18:25:12 UTC 2020

Hi fellow coders, I spent a couple of hours to implement a 
working, basic, quicksort. Practicing D. It finally boils down to 
that (intent to use the std, not to rewrite swap, etc):

import std.stdio : writeln;
import std.algorithm.sorting;

pure void quickSort(T) (T[] r)
   if (r.length > 1)
     size_t p = pivotPartition(r, r.length-1);  //r[$-1] is 
swapped to r[p]

     quickSort( r[ 0..p ] );
     quickSort( r[ p+1..$ ] );

void main()
   int[] arr = [9,7, 4 , 8, 5, 3, 1];
   writeln("arr : ", arr );


I spent some time understanding "ranges", but at the end I am 
surprised I didn't use them. At the beginning I wrote something 
like quickSort( Range r ) and tried randomaccessrange etc but I 
didn't manage to make it work.

My question is, is there a way to write this with "ranges" as the 
argument, or does this concept of slices with the [] notation 
takes precedence somehow on the concept of ranges, in this 
particular case?

2) how would YOU write it? Using std or not.

3) any comment/code correction welcome, I am learning :)


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