blob: 54f858bb4abad5de15ad6ec78638e178529b5fc1 (
plain)
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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
#!/usr/bin/perl
#
# Perl Weekly Challenge - 071
#
# Task #2: Trim Linked List
#
# https://perlweeklychallenge.org/blog/perl-weekly-challenge-071/
#
package Node;
use Moo;
has v => (is => 'rw');
has p => (is => 'rw');
sub trim {
my ($self, $position) = @_;
die "ERROR: Invalid position [$position].\n"
unless ($position =~ /^\d+$/);
my $tail = $self;
my $count = 1;
my $node;
while ($tail->p) {
if ($position > $count) {
$node = $tail;
}
elsif ($position == $count) {
if (defined $node) {
# Remove current node by making the
# parent of current node as parent
# of previous node
$node->p($tail->p);
}
else {
# If you're taking first from the end
# then return the parent of last node
return $tail->p;
}
}
$tail = $tail->p;
$count++;
}
# Take the first node off if and only if:
# a) you reached the first node or
# b) given position is more than the total nodes
$node->p(undef) if ($count <= $position);
return $self;
}
sub show {
my ($self) = @_;
my $node = $self;
my @v = ();
while ($node->p) {
push @v, $node->v;
$node = $node->p;
}
push @v, $node->v;
return join ' -> ', reverse @v;
}
package main;
my $L = $ARGV[0] || '1 -> 2 -> 3 -> 4 -> 5';
my $N = $ARGV[1] || 2;
print create_linked_list($L)->trim($N)->show, "\n";
#
#
# METHOD
sub create_linked_list {
my ($list) = @_;
$list =~ s/\s+//g;
die "ERROR: Invalid list [$list].\n"
if ($list !~ /\-\>/);
$list = [ split /\-\>/, $list ];
my $node = Node->new(v => pop @$list);
my $tail = $node;
while (@$list) {
my $_node = Node->new(v => pop @$list);
$tail->p($_node);
$tail = $_node;
}
print $node->show, "\n";
return $node;
}
|
