perl code for challenge 70 task 1

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+#!/usr/bin/env perl
+use strict;
+use warnings;
+use feature qw(:5.32);
+use experimental qw(signatures);
+
+# TASK #1 › Character Swapping
+# Submitted by: Mohammad S Anwar
+#
+# 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, $C <= $O and $C + $O <= $N.
+#
+# UPDATE: 2020-07-20 16:10:00 Pete Houston suggested to put additional
+# constraint i.e. $C <= $O. He presented the use case $S = 'abcd', $C
+# = 2, $O = 1.
+#
+# 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
+#     $O = 4
+#
+# Character Swapping:
+#     swap 1: e <=> n = pnrlaedraku
+#     swap 2: r <=> d = pndlaerraku
+#     swap 3: l <=> r = pndraerlaku
+#
+# Output:
+#     pndraerlaku
+
+my ($s, $c, $o) = @ARGV;
+my $n = length($s);
+
+for my $i (1..$c) {
+    (substr($s, $i % $n,        1), substr($s, ($i + $o) % $n, 1)) =
+    (substr($s, ($i + $o) % $n, 1), substr($s, $i % $n,        1));
+}
+
+say $s;