From dae0a10e23b470229e2440cd0683b3a90a1e4ca4 Mon Sep 17 00:00:00 2001
From: James Smith <js5@sanger.ac.uk>
Date: Mon, 26 Dec 2022 01:06:51 +0000
Subject: Update README.md

---
 challenge-196/james-smith/README.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/challenge-196/james-smith/README.md b/challenge-196/james-smith/README.md
index 2a84b66e88..5c485666aa 100644
--- a/challenge-196/james-smith/README.md
+++ b/challenge-196/james-smith/README.md
@@ -75,3 +75,19 @@ sub range_v2 {
   grep { $_->[1]-$_->[0] } @r
 }
 ```
+
+### Version 3
+
+Finally one last method - where we use `for` rather than `shift`/`while` which is the fastest...
+
+We just for over `@_`; If `$_` is equal to the `$end+1` we extend the region, o/w we push the interval if it is not "empty" (`$s==$e`), and start a new interval.
+Finally at the end we add the last interval if non-empty.
+
+```perl
+sub range_for {
+  my $s = my $e = shift, my @r;
+  ($_==$e+1) ? $e++ : ( $s==$e || push(@r,[$s,$e]) , $e=$s=$_ ) for @_;
+  push @r, [$s,$e] unless $s==$e;
+  @r
+}
+```
-- 
cgit