The weekly challenge 321 - Task 1: Distinct Average

 1 #!/usr/bin/env perl
 2 # https://theweeklychallenge.org/blog/perl-weekly-challenge-321/#TASK1
 3 #
 4 # Task 1: Distinct Average
 5 # ========================
 6 #
 7 # You are given an array of numbers with even length.
 8 #
 9 # Write a script to return the count of distinct average. The average is
10 # calculate by removing the minimum and the maximum, then average of the two.
11 #
12 ## Example 1
13 ##
14 ## Input: @nums = (1, 2, 4, 3, 5, 6)
15 ## Output: 1
16 ##
17 ## Step 1: Min = 1, Max = 6, Avg = 3.5
18 ## Step 2: Min = 2, Max = 5, Avg = 3.5
19 ## Step 3: Min = 3, Max = 4, Avg = 3.5
20 ##
21 ## The count of distinct average is 1.
22 #
23 #
24 ## Example 2
25 ##
26 ## Input: @nums = (0, 2, 4, 8, 3, 5)
27 ## Output: 2
28 ##
29 ## Step 1: Min = 0, Max = 8, Avg = 4
30 ## Step 2: Min = 2, Max = 5, Avg = 3.5
31 ## Step 3: Min = 3, Max = 4, Avg = 3.5
32 ##
33 ## The count of distinct average is 2.
34 #
35 #
36 ## Example 3
37 ##
38 ## Input: @nums = (7, 3, 1, 0, 5, 9)
39 ## Output: 2
40 ##
41 ## Step 1: Min = 0, Max = 9, Avg = 4.5
42 ## Step 2: Min = 1, Max = 7, Avg = 4
43 ## Step 3: Min = 3, Max = 5, Avg = 4
44 ##
45 ## The count of distinct average is 2.
46 #
47 ############################################################
48 ##
49 ## discussion
50 ##
51 ############################################################
52 #
53 # At first, we sort the array. Then we can always remove the last
54 # and first element via pop() and shift() until there are no more
55 # elements in the array. Of course we calculate the medium value at
56 # each step and take note of it so in the end we can have the number
57 # of distinct averages.
58 
59 use v5.36;
60 use List::Util qw(sum);
61 
62 distinct_average(1, 2, 4, 3, 5, 6);
63 distinct_average(0, 2, 4, 8, 3, 5);
64 distinct_average(7, 3, 1, 0, 5, 9);
65 
66 sub distinct_average(@nums) {
67     say "Input: (" . join(", ", @nums) . ")";
68     my @sorted = sort { $a <=> $b } @nums;
69     my $avg = {};
70     while(scalar(@sorted)) {
71         my $s = sum(@sorted);
72         my $average = $s / scalar(@sorted);
73         $avg->{$average} = 1;
74         pop @sorted;
75         shift @sorted;
76     }
77     my $count = scalar(keys(%$avg));
78     say "Output: $count";
79 }