Create ch-2.pl

Two solutions a hacky array one which counts...

But then a second faster one that only works on the first three entries in the array

1 files changed, 47 insertions, 0 deletions

diff --git a/challenge-193/james-smith/perl/ch-2.pl b/challenge-193/james-smith/perl/ch-2.pl
new file mode 100644
index 0000000000..2c004a7e6c
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+++ b/challenge-193/james-smith/perl/ch-2.pl
@@ -0,0 +1,47 @@
+#!/usr/local/bin/perl
+
+use strict;
+use warnings;
+use feature qw(say);
+use Test::More;
+
+my @list1 = ( 'bob', map { chr(97+rand(26)) x 3 } 1..10000 );
+my @list2 = (      ( map { chr(97+rand(26)) x 3 } 1..10000 ), 'bob' );
+my @TESTS = (
+  [ [qw(adc wzy abc)],     'abc' ],
+  [ [qw(aaa bob ccc ddd)], 'bob' ],
+  [ [@list1],              'bob' ],
+  [ [@list2],              'bob' ],
+);
+
+is( odd_string_array( @{$_->[0]} ), $_->[1] ) for @TESTS;
+is( odd_string_fast(  @{$_->[0]} ), $_->[1] ) for @TESTS;
+
+sub odd_string_array {
+  my %x;
+  ## Keyed by signature - so one key will have
+  push @{$x{
+      ord( substr $_, 1 ) *  99
+    + ord( substr $_, 2 )
+    - ord( $_           ) * 100
+  }}, $_ for @_;
+  [ grep { @{$_}==1 } values %x ]->[0][0]
+}
+
+sub odd_string_fast {
+  my($x1,$x2,$y1,$y2,$z1,$z2) = (
+    ord($_[0]) - ord(substr$_[0],1), ord($_[0]) - ord(substr$_[0],2),
+    ord($_[1]) - ord(substr$_[1],1), ord($_[1]) - ord(substr$_[1],2),
+    ord($_[2]) - ord(substr$_[2],1), ord($_[2]) - ord(substr$_[2],2),
+  );
+  if( $x1 == $y1 && $x2 == $y2 ) { ## First & second match so NOT 1st
+    if( $x1 == $z1 && $x2 == $z2 ) { ## Third matches first - so find first which doesn't
+      ( $x1 != ord($_) - ord(substr$_,1) || $x2 != ord($_) - ord(substr$_,2) ) && return $_ for @_[3..$#_];
+    } else {
+      return $_[2];
+    }
+  } ## Different so it must be 1st or ceons
+  $_[ $x1 == $z1 && $x2 == $z2 ? 1 : 0 ]
+}
+
+