perl code for challenge 70 task 2

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+#!/usr/bin/env perl
+use strict;
+use warnings;
+use feature qw(:5.32);
+use experimental qw(signatures);
+
+# TASK #2 › Gray Code Sequence
+# Submitted by: Mohammad S Anwar
+#
+# You are given an integer 2 <= $N <= 5.
+#
+# Write a script to generate $N-bit gray code sequence.
+#
+# 2-bit Gray Code Sequence
+#
+# [0, 1, 3, 2]
+#
+# 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]
+
+my $n = $ARGV[0];
+my @S = (0, 1, 3, 2);
+
+for my $i (3..$n) {
+    @S = gray_code($i, @S);
+}
+
+say "@S";
+
+sub gray_code($n, @S) {
+    my @S2 = map { "1$_" } reverse map { scalar sprintf "%.*b", $n-1, $_ } @S;
+    return @S, map { eval "0b$_" } @S2;
+}