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
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
#!perl
################################################################################
=comment
Perl Weekly Challenge 339
=========================
TASK #2
-------
*Peak Point*
Submitted by: Mohammad Sajid Anwar
You are given an array of altitude gain.
Write a script to find the peak point gained.
Example 1
Input: @gain = (-5, 1, 5, -9, 2)
Output: 1
start: 0
1st change: 0 + (-5) = -5
2nd change: -5 + 1 = -4
3rd change: -4 + 5 = 1
4th change: 1 + (-9) = -8
5th change: -8 + 2 = -6
max(0, -5, -4, 1, -8, -6) = 1
Example 2
Input: @gain = (10, 10, 10, -25)
Output: 30
start: 0
1st change: 0 + 10 = 10
2nd change: 10 + 10 = 20
3rd change: 20 + 10 = 30
4th change: 30 + (-25) = 5
max(0, 10, 20, 30, 5) = 30
Example 3
Input: @gain = (3, -4, 2, 5, -6, 1)
Output: 6
start: 0
1st change: 0 + 3 = 3
2nd change: 3 + (-4) = -1
3rd change: -1 + 2 = 1
4th change: 1 + 5 = 6
5th change: 6 + (-6) = 0
6th change: 0 + 1 = 1
max(0, 3, -1, 1, 6, 0, 1) = 6
Example 4
Input: @gain = (-1, -2, -3, -4)
Output: 0
start: 0
1st change: 0 + (-1) = -1
2nd change: -1 + (-2) = -3
3rd change: -3 + (-3) = -6
4th change: -6 + (-4) = -10
max(0, -1, -3, -6, -10) = 0
Example 5
Input: @gain = (-10, 15, 5)
Output: 10
start: 0
1st change: 0 + (-10) = -10
2nd change: -10 + 15 = 5
3rd change: 5 + 5 = 10
max(0, -10, 5, 10) = 10
=cut
################################################################################
#--------------------------------------#
# Copyright © 2025 PerlMonk Athanasius #
#--------------------------------------#
#===============================================================================
=comment
Assumption
----------
Altitude gains are integers.
Interface
---------
1. If no command-line arguments are given, the test suite is run. Otherwise:
2. A non-empty list of integers is entered on the command-line.
=cut
#===============================================================================
use v5.38.2; # Enables strictures
use warnings;
use Const::Fast;
use Regexp::Common qw( number );
use Test::More;
const my $USAGE => <<END;
Usage:
perl $0 [<gain> ...]
perl $0
[<gain> ...] A non-empty list of altitude gains (integers)
END
#-------------------------------------------------------------------------------
BEGIN
#-------------------------------------------------------------------------------
{
$| = 1;
print "\nChallenge 339, Task #2: Peak Point (Perl)\n\n";
}
#===============================================================================
MAIN:
#===============================================================================
{
if (scalar @ARGV == 0)
{
run_tests();
}
else
{
my @gain = @ARGV;
for (@gain)
{
/ ^ $RE{num}{int} $ /x or error( qq["$_" is not a valid integer] );
}
printf "Input: \@gain = (%s)\n", join ', ', @gain;
my $peak = find_peak_point( \@gain );
print "Output: $peak\n";
}
}
#-------------------------------------------------------------------------------
sub find_peak_point
#-------------------------------------------------------------------------------
{
my ($gains) = @_;
my $peak = 0;
my $altitude = 0; # Start
for my $gain (@$gains)
{
$altitude += $gain;
$peak = $altitude if $altitude > $peak;
}
return $peak;
}
#-------------------------------------------------------------------------------
sub run_tests
#-------------------------------------------------------------------------------
{
print "Running the test suite\n";
while (my $line = <DATA>)
{
chomp $line;
my ($test_name, $gains_str, $expected) = split / \| /x, $line;
for ($test_name, $gains_str, $expected)
{
s/ ^ \s+ //x;
s/ \s+ $ //x;
}
my @gain = split / \s+ /x, $gains_str;
my $peak = find_peak_point( \@gain );
is $peak, $expected, $test_name;
}
done_testing;
}
#-------------------------------------------------------------------------------
sub error
#-------------------------------------------------------------------------------
{
my ($message) = @_;
die "ERROR: $message\n$USAGE";
}
################################################################################
__DATA__
Example 1| -5 1 5 -9 2 | 1
Example 2| 10 10 10 -25 |30
Example 3| 3 -4 2 5 -6 1| 6
Example 4| -1 -2 -3 -4 | 0
Example 5|-10 15 5 |10
|
