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
|
#!/usr/bin/perl
use warnings;
use strict;
use enum qw( ARRIVAL DEPARTURE );
sub minimum_platforms {
my ($arr, $dep) = @_;
die 'Different number of arrivals and departures'
unless @$arr == @$dep;
my @times = sort { $a->[0] <=> $b->[0] } (map [s/://r, ARRIVAL], @$arr),
(map [s/://r, DEPARTURE], @$dep);
my ($current, $max) = (0, 0);
# To handle trains staying over midnight, simulate two consecutive days.
push @times, @times;
while (@times) {
my $time = shift @times;
# On the first day, ignore the departing trains that arrived
# on the previous day.
next if DEPARTURE eq $time->[1] && 0 == $current;
+{(ARRIVAL) => sub { ++$current },
(DEPARTURE) => sub { --$current }}->{ $time->[1] }();
$max = $current if $current > $max;
}
return $max
}
use Test2::V0;
plan 7;
is minimum_platforms([qw[ 11:20 14:30 ]], [qw[ 11:50 15:00 ]]), 1, 'Example 1';
is minimum_platforms([qw[ 10:20 11:00 11:10 12:20 16:20 19:00 ]],
[qw[ 10:30 13:20 12:40 12:50 20:20 21:20 ]]),
3, 'Example 2';
is minimum_platforms([], []), 0, 'No trains, no platforms';
is minimum_platforms([qw[ 23:00 ]], [qw[ 1:00 ]]), 1, 'one overnight';
is minimum_platforms([qw[ 23:00 23:15 ]], [qw[ 1:00 0:40 ]]),
2, 'two overnight';
is minimum_platforms([qw[ 23:00 23:15 23:30 ]], [qw[ 1:00 0:40 23:50 ]]),
3, 'two overnight + 1';
is minimum_platforms([qw[ 10:01 10:02 13:01 13:02 13:03 ]],
[qw[ 11:01 11:02 12:01 12:02 12:03 ]]),
5, 'three overnight + 2';
|
