Solutions to challenge-070.

2 files changed, 120 insertions, 0 deletions

diff --git a/challenge-070/wanderdoc/perl/ch-1.pl b/challenge-070/wanderdoc/perl/ch-1.pl
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+++ b/challenge-070/wanderdoc/perl/ch-1.pl
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+#!perl
+use strict;
+use warnings FATAL => qw(all);
+
+=prompt
+You are given a string $S of size $N. You are also given swap count $C and offset $O such that $C >= 1, $O >= 1 and $C + $O <= $N.
+
+Write a script to perform character swapping like below:
+$S[ 1 % $N ] <=> $S[ (1 + $O) % $N ]
+$S[ 2 % $N ] <=> $S[ (2 + $O) % $N ]
+$S[ 3 % $N ] <=> $S[ (3 + $O) % $N ] ...
+$S[ $C % $N ] <=> $S[ ($C + $O) % $N ]
+
+Example 1
+Input: $S = 'perlandraku' $C = 3 $O = 4
+
+Character Swapping:
+    swap 1: e <=> n = pnrlaedraku
+    swap 2: r <=> d = pndlaerraku
+    swap 3: l <=> r = pndraerlaku
+
+Output:  pndraerlaku
+
+Example 2
+Input: $S = 'weeklychallenge' $C = 5 $O = 2
+
+Character Swapping:
+    swap 1: e <=> k = wkeelychallenge
+    swap 2: e <=> l = wkleeychallenge
+    swap 3: e <=> y = wklyeechallenge
+    swap 4: e <=> c = wklyceehallenge
+    swap 5: e <=> h = wklycheeallenge
+
+Output: wklycheeallenge
+=cut
+
+use Test::More;
+
+
+
+sub swapping
+{
+     my $string = $_[0];
+
+     my $count = $_[1];
+     my $offset = $_[2];
+     my $len = length($string);
+
+
+     my $i = 1;
+
+     while ( $i <= $count )
+     {
+          (substr($string, $i % $len, 1), substr($string, ($i + $offset) % $len, 1)) =
+          (substr($string, ($i + $offset) % $len, 1), substr($string, $i % $len, 1));
+          $i++;
+     }
+
+     return $string;
+}
+is(swapping('perlandraku', 3, 4), 'pndraerlaku', 'Example 1');
+is(swapping('weeklychallenge', 5, 2), 'wklycheeallenge', 'Example 2');
+done_testing();
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diff --git a/challenge-070/wanderdoc/perl/ch-2.pl b/challenge-070/wanderdoc/perl/ch-2.pl
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+++ b/challenge-070/wanderdoc/perl/ch-2.pl
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+#!perl
+use strict;
+use warnings FATAL => qw(all);
+
+=prompt
+You are given an integer 2 <= $N <= 5.
+
+Write a script to generate $N-bit gray code sequence.
+To generate the 3-bit Gray code sequence from the 2-bit Gray code sequence, follow the step below:
+
+2-bit Gray Code sequence [0, 1, 3, 2]
+
+
+Binary form of the sequence a) S1 = [00, 01, 11, 10]
+Reverse of S1 b) S2 = [10, 11, 01, 00]
+Prefix all entries of S1 with '0' c) S1 = [000, 001, 011, 010]
+Prefix all entries of S2 with '1' d) S2 = [110, 111, 101, 100]
+Concatenate S1 and S2 gives 3-bit Gray Code sequence e) [000, 001, 011, 010, 110, 111, 101, 100]
+3-bit Gray Code sequence [0, 1, 3, 2, 6, 7, 5, 4]
+
+Example
+Input: $N = 4
+Output: [0, 1, 3, 2, 6, 7, 5, 4, 12, 13, 15, 14, 10, 11, 9, 8]
+
+=cut
+
+use Test::More;
+sub gray_code
+{
+     my @seq = @{$_[0]};
+     my $cnt = $_[1];
+
+     my $bit = $_[2];
+     
+     while ( $cnt < $bit )
+     {
+          @seq = map sprintf("%0${cnt}b",$_), @seq;
+          my @seq_2 = reverse @seq;
+
+
+          @seq   = map '0' . $_, @seq;
+          @seq_2 = map '1' . $_, @seq_2;
+          push @seq, @seq_2;
+
+          @seq = map oct("0b".$_), @seq;
+          $cnt++;
+     }
+     return @seq;
+
+}
+
+is_deeply([gray_code([0, 1, 3, 2], 2, 3)], ([0, 1, 3, 2, 6, 7, 5, 4]), 'Example 1');
+is_deeply([gray_code([0, 1, 3, 2], 2, 4)], 
+     ([0, 1, 3, 2, 6, 7, 5, 4, 12, 13, 15, 14, 10, 11, 9, 8]), 'Example 2');
+is_deeply([gray_code([0, 1, 3, 2, 6, 7, 5, 4], 3, 4)],
+     ([0, 1, 3, 2, 6, 7, 5, 4, 12, 13, 15, 14, 10, 11, 9, 8]), 'Variation');
+done_testing();
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