1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
# 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: $N = 4
#
# Output: [0, 1, 3, 2, 6, 7, 5, 4, 12, 13, 15, 14, 10, 11, 9, 8]
sub gray-code-sequence($n) {
if ($n == 1) {
return [0, 1];
}
my $seq1 = gray-code-sequence($n - 1);
my $seq2 = [2**($n - 1) + $_ for $seq1.reverse];
return [|($seq1), |($seq2)];
}
gray-code-sequence(1).say;
gray-code-sequence(2).say;
gray-code-sequence(3).say;
gray-code-sequence(4).say;
gray-code-sequence(5).say;
|
