Merge pull request #10735 from JTimothyKing/challenge-284

Solutions to challenge 284.

7 files changed, 134 insertions, 0 deletions

diff --git a/challenge-284/jtimothyking/README b/challenge-284/jtimothyking/README
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index 0000000000..9bbfb44116
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+++ b/challenge-284/jtimothyking/README
@@ -0,0 +1 @@
+Solution by Tim King.
diff --git a/challenge-284/jtimothyking/csharp/InputParsingExtensions.cs b/challenge-284/jtimothyking/csharp/InputParsingExtensions.cs
new file mode 100644
index 0000000000..d048e85f59
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+++ b/challenge-284/jtimothyking/csharp/InputParsingExtensions.cs
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+using System.Text.RegularExpressions;
+
+namespace PwcLib;
+
+public static class InputParsingExtensions
+{
+    /// <summary>
+    ///    Parses a line of the form "@<symbol> = (1, 2, 3)" into an array of integers.
+    /// </summary>
+    public static int[] GetInts(this string line, string symbol = "ints")
+    {
+        var match = Regex.Match(line, $@"
+            \A \s*
+            \@{symbol} \s* = \s* \(
+                ( \d+ (?: \s* , \s* \d+ )* )
+            \)
+            \s* \z
+        ", RegexOptions.IgnorePatternWhitespace);
+        if (!match.Success)
+            throw new ArgumentException($"Invalid input: {line}", nameof(line));
+        return match.Groups[1].Value.Split(", ").Select(int.Parse).ToArray();
+    }
+}
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diff --git a/challenge-284/jtimothyking/csharp/LuckyInteger.cs b/challenge-284/jtimothyking/csharp/LuckyInteger.cs
new file mode 100644
index 0000000000..809514c185
--- /dev/null
+++ b/challenge-284/jtimothyking/csharp/LuckyInteger.cs
@@ -0,0 +1,21 @@
+using PwcLib;
+
+namespace _1_lucky_integer;
+
+public static class LuckyInteger
+{
+    public static void Main(string[] args)
+    {
+        var input = Console.ReadLine() ?? "";
+        var luckyInteger = input.GetInts().FindLargestLuckyInteger();
+        Console.WriteLine(luckyInteger);
+    }
+
+    private static int FindLargestLuckyInteger(this int[] ints) =>
+        ints
+            .GroupBy(x => x)
+            .Where(grouping => grouping.Count() == grouping.Key)
+            .Select(grouping => grouping.Key)
+            .OrderByDescending(x => x)
+            .FirstOrDefault(defaultValue: -1);
+}
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diff --git a/challenge-284/jtimothyking/csharp/RelativeSort.cs b/challenge-284/jtimothyking/csharp/RelativeSort.cs
new file mode 100644
index 0000000000..418517ef78
--- /dev/null
+++ b/challenge-284/jtimothyking/csharp/RelativeSort.cs
@@ -0,0 +1,33 @@
+using PwcLib;
+
+namespace _2_relative_sort;
+
+public static class RelativeSort
+{
+    public static void Main(string[] args)
+    {
+        var line1 = Console.ReadLine() ?? "";
+        var line2 = Console.ReadLine() ?? "";
+        var sortedInts = line1.GetInts("list1")
+            .OrderRelativeTo(line2.GetInts("list2"));
+        Console.WriteLine($"({string.Join(", ", sortedInts)})");
+    }
+
+    /// <summary>
+    ///    Orders the elements of the source list relative to the order of the reference list.
+    /// </summary>
+    private static int[] OrderRelativeTo(this IEnumerable<int> source, IEnumerable<int> reference)
+    {
+        var rank = reference.ToRankDictionary();
+        return source
+            .OrderBy(x => rank.GetValueOrDefault(x, defaultValue: x + rank.Count))
+            .ToArray();
+    }
+
+    /// <summary>
+    ///     Returns a dictionary that maps each element of the source to its index in the source.
+    /// </summary>
+    private static Dictionary<TSource, int> ToRankDictionary<TSource>(this IEnumerable<TSource> source)
+        where TSource : notnull =>
+        source.Select((x, i) => (x, i)).ToDictionary(xi => xi.x, xi => xi.i);
+}
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diff --git a/challenge-284/jtimothyking/perl/1-lucky-integer.pl b/challenge-284/jtimothyking/perl/1-lucky-integer.pl
new file mode 100644
index 0000000000..28260c9ea3
--- /dev/null
+++ b/challenge-284/jtimothyking/perl/1-lucky-integer.pl
@@ -0,0 +1,16 @@
+#!/usr/bin/perl
+use v5.38;
+use InputParsing;
+
+my $input = <STDIN>;
+my $lucky_int = find_largest_lucky_int(InputParsing::get_ints($input));
+say $lucky_int;
+
+sub find_largest_lucky_int {
+    my %counts;
+    $counts{$_}++ for @_;
+    my @lucky_ints = grep { $counts{$_} == $_ } keys %counts;
+    return @lucky_ints ? (sort { $b <=> $a } @lucky_ints)[0] : -1;
+}
+
+__END__
diff --git a/challenge-284/jtimothyking/perl/2-relative-sort.pl b/challenge-284/jtimothyking/perl/2-relative-sort.pl
new file mode 100644
index 0000000000..f32ff6aa57
--- /dev/null
+++ b/challenge-284/jtimothyking/perl/2-relative-sort.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+use v5.38;
+use InputParsing;
+
+my $input_line_1 = <STDIN>;
+my $input_line_2 = <STDIN>;
+my $sorter = relative_to(InputParsing::get_ints($input_line_2, 'list2'));
+my @sorted_list = sort $sorter InputParsing::get_ints($input_line_1, 'list1');
+say '(' . join(', ', @sorted_list) . ')';
+
+sub relative_to {
+    my $next_rank = 0;
+    my %rank = map { $_ => $next_rank++ } @_;
+    return sub {
+        return ($rank{$a} // $a + $next_rank) <=> ($rank{$b} // $b + $next_rank);
+    };
+}
+
+__END__
diff --git a/challenge-284/jtimothyking/perl/InputParsing.pm b/challenge-284/jtimothyking/perl/InputParsing.pm
new file mode 100644
index 0000000000..4fdfe13a14
--- /dev/null
+++ b/challenge-284/jtimothyking/perl/InputParsing.pm
@@ -0,0 +1,21 @@
+package InputParsing;
+use v5.38;
+
+sub get_ints {
+    my ($line, $symbol) = @_;
+    $symbol //= 'ints';
+    chomp($line);
+    $line =~ m[
+        \A \s*
+        \@$symbol \s* = \s* \(
+            ( \d+ (?: \s* , \s* \d+ )* )
+        \)
+        \s* \z
+    ]x;
+    my @ints = split /\s*,\s*/, $1 // '';
+    @ints or die "Invalid line for $symbol: $line\n";
+    return @ints;
+}
+
+
+1;
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