blob: 5b663dae9165c37686e99cade3350e7f1bc8d38a (
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
|
use strict;
use warnings;
use feature qw'say signatures';
no warnings 'experimental::signatures';
use constant DEBUG => $ENV{DEBUG} // 0;
run() unless caller();
sub run() {
my $i = prompt_for_integer('i');
my $j = prompt_for_integer('j');
my $k = prompt_for_integer('k');
my $max = $i * $j;
if ( $k > $max ) {
die "Index 'k' ($k) is larger than the table. Max: $max\n";
}
my $matrix = multiplication_matrix( $i, $j );
my @sorted_matrix = sort_multiplication_matrix($matrix);
my $res = $sorted_matrix[ $k - 1 ];
if (DEBUG) {
say "Since the multiplication of $i x $j is as below:";
say render_matrix($matrix);
say "The sorted multiplication table:";
say join( ' ', @sorted_matrix );
say "Now the " . to_ordinal($k) . " element in the table is '$res'";
}
say $res;
}
sub multiplication_matrix ( $i, $j ) {
[
map {
my $row = $_;
[
map {
my $col = $_;
$col * $row;
} ( 1 .. $j )
];
} ( 1 .. $i )
];
}
sub sort_multiplication_matrix($matrix) {
sort { $a <=> $b } map { @$_ } @$matrix;
}
sub render_matrix($matrix) {
my $max = $matrix->[-1][-1];
my $width = length $max;
my $format_str = "%$width" . 'd';
join(
"\n",
map {
join( " ", map { sprintf( $format_str, $_ ) } @$_ )
} @$matrix
);
}
sub to_ordinal($n) {
return ( $n == 1 ) ? "1st" : $n == 2 ? "2nd" : $n == 3 ? "3rd" : $n . 'th';
}
sub prompt_for_integer($name) {
say "Enter integer number $name greater or equal to 1.";
chomp( my $number = <STDIN> );
if ( $number !~ m/^\d+$/ || $number < 1 ) {
say "Invalid integer.";
return prompt_for_integer($name);
}
return $number;
}
|
