Add solution 321.

Signed-off-by: Thomas Köhler <jean-luc@picard.franken.de>

4 files changed, 146 insertions, 0 deletions

diff --git a/challenge-321/jeanluc2020/blog-1.txt b/challenge-321/jeanluc2020/blog-1.txt
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+http://gott-gehabt.de/800_wer_wir_sind/thomas/Homepage/Computer/perl/theweeklychallenge-321-1.html
diff --git a/challenge-321/jeanluc2020/blog-2.txt b/challenge-321/jeanluc2020/blog-2.txt
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+http://gott-gehabt.de/800_wer_wir_sind/thomas/Homepage/Computer/perl/theweeklychallenge-321-2.html
diff --git a/challenge-321/jeanluc2020/perl/ch-1.pl b/challenge-321/jeanluc2020/perl/ch-1.pl
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+#!/usr/bin/env perl
+# https://theweeklychallenge.org/blog/perl-weekly-challenge-321/#TASK1
+#
+# Task 1: Distinct Average
+# ========================
+#
+# You are given an array of numbers with even length.
+#
+# Write a script to return the count of distinct average. The average is
+# calculate by removing the minimum and the maximum, then average of the two.
+#
+## Example 1
+##
+## Input: @nums = (1, 2, 4, 3, 5, 6)
+## Output: 1
+##
+## Step 1: Min = 1, Max = 6, Avg = 3.5
+## Step 2: Min = 2, Max = 5, Avg = 3.5
+## Step 3: Min = 3, Max = 4, Avg = 3.5
+##
+## The count of distinct average is 1.
+#
+#
+## Example 2
+##
+## Input: @nums = (0, 2, 4, 8, 3, 5)
+## Output: 2
+##
+## Step 1: Min = 0, Max = 8, Avg = 4
+## Step 2: Min = 2, Max = 5, Avg = 3.5
+## Step 3: Min = 3, Max = 4, Avg = 3.5
+##
+## The count of distinct average is 2.
+#
+#
+## Example 3
+##
+## Input: @nums = (7, 3, 1, 0, 5, 9)
+## Output: 2
+##
+## Step 1: Min = 0, Max = 9, Avg = 4.5
+## Step 2: Min = 1, Max = 7, Avg = 4
+## Step 3: Min = 3, Max = 5, Avg = 4
+##
+## The count of distinct average is 2.
+#
+############################################################
+##
+## discussion
+##
+############################################################
+#
+# At first, we sort the array. Then we can always remove the last
+# and first element via pop() and shift() until there are no more
+# elements in the array. Of course we calculate the medium value at
+# each step and take note of it so in the end we can have the number
+# of distinct averages.
+
+use v5.36;
+use List::Util qw(sum);
+
+distinct_average(1, 2, 4, 3, 5, 6);
+distinct_average(0, 2, 4, 8, 3, 5);
+distinct_average(7, 3, 1, 0, 5, 9);
+
+sub distinct_average(@nums) {
+    say "Input: (" . join(", ", @nums) . ")";
+    my @sorted = sort { $a <=> $b } @nums;
+    my $avg = {};
+    while(scalar(@sorted)) {
+        my $s = sum(@sorted);
+        my $average = $s / scalar(@sorted);
+        $avg->{$average} = 1;
+        pop @sorted;
+        shift @sorted;
+    }
+    my $count = scalar(keys(%$avg));
+    say "Output: $count";
+}
diff --git a/challenge-321/jeanluc2020/perl/ch-2.pl b/challenge-321/jeanluc2020/perl/ch-2.pl
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+#!/usr/bin/env perl
+# https://theweeklychallenge.org/blog/perl-weekly-challenge-321/#TASK2
+#
+# Task 2: Backspace Compare
+# =========================
+#
+# You are given two strings containing zero or more #.
+#
+# Write a script to return true if the two given strings are same by treating #
+# as backspace.
+#
+## Example 1
+##
+## Input: $str1 = "ab#c"
+##        $str2 = "ad#c"
+## Output: true
+##
+## For first string,  we remove "b" as it is followed by "#".
+## For second string, we remove "d" as it is followed by "#".
+## In the end both strings became the same.
+#
+#
+## Example 2
+##
+## Input: $str1 = "ab##"
+##        $str2 = "a#b#"
+## Output: true
+#
+#
+## Example 3
+##
+## Input: $str1 = "a#b"
+##        $str2 = "c"
+## Output: false
+#
+############################################################
+##
+## discussion
+##
+############################################################
+#
+# As long as there's a # in the word following another character, we replce
+# both the # character and the character before it. Once done on both characters,
+# a simple string comparison shows whether the two strings are equal.
+
+use v5.36;
+
+backspace_compare( "ab#c", "ad#c" );
+backspace_compare( "ab##", "a#b#" );
+backspace_compare( "a#b", "c");
+
+sub backspace_compare($str1, $str2) {
+    say "\$str1 = $str1, \$str2 = $str2";
+    while($str1 =~ m/[^#]#/) {
+        $str1 =~ s/[^#]#//;
+    }
+    while($str2 =~ m/[^#]#/) {
+        $str2 =~ s/[^#]#//;
+    }
+    if($str1 eq $str2) {
+        say "Output: true";
+    } else {
+        say "Output: false";
+    }
+}