Add TWC 216 solutions by Bruce Gray (Raku only).

2 files changed, 113 insertions, 0 deletions

diff --git a/challenge-216/bruce-gray/raku/ch-1.raku b/challenge-216/bruce-gray/raku/ch-1.raku
new file mode 100644
index 0000000000..116fba06fe
--- /dev/null
+++ b/challenge-216/bruce-gray/raku/ch-1.raku
@@ -0,0 +1,17 @@
+sub task1 ( @words, Str $reg --> Seq ) {
+
+    my Set $r = $reg.lc.comb(/<alpha>/).Set;
+
+    return @words.grep: *.lc.comb ⊇ $r;
+}
+
+my @tests =
+    ( <abc abcd bcd>    , 'AB1 2CD' , <abcd>      ),
+    ( <job james bjorg> , '007 JB'  , <job bjorg> ),
+    ( <crack road rac>  , 'C7 RA2'  , <crack rac> ),
+;
+use Test;
+plan +@tests;
+for @tests -> ( $in_words, $in_reg, $expected ) {
+    is    task1($in_words, $in_reg),$expected;
+}
diff --git a/challenge-216/bruce-gray/raku/ch-2.raku b/challenge-216/bruce-gray/raku/ch-2.raku
new file mode 100644
index 0000000000..d52db82857
--- /dev/null
+++ b/challenge-216/bruce-gray/raku/ch-2.raku
@@ -0,0 +1,96 @@
+# We will need three general structures, or set of structures.
+# 1. Fixed summary of letters in @stickers
+# 2. Mutable info on what letters in $word still need a sticker to contribute.
+# 3. All the letters from all the stickers that have been purchased, but not yet used in $word.
+
+# All the letters that have only one source sticker must be handled first (or as a first step on every iteration/recursion)
+
+sub task2 ( @stickers, Str $word --> UInt ) {
+    return 0 if $word.comb.Set (-) @stickers».comb.flat.Set;
+
+    my BagHash $word_letters = $word.comb.BagHash;
+
+    # my @sticker_letters = @stickers.map: *.comb.Bag;
+    my @sticker_letters = @stickers.map: *.comb.grep({ $word_letters{$_} }).Bag; # Reduces to just useful letters
+
+    my %letter_sources; # XXX Change to build via a multi-level .classify or .categorize?
+    my %letter_source_count;
+    for @sticker_letters.kv -> UInt $index, Bag $sl {
+        for $sl.kv -> Str $letter, UInt $count {
+            warn if defined %letter_sources{$letter}[$index];
+            %letter_sources{$letter}[$index] = $count;
+            %letter_source_count{$letter}++;
+        }
+    }
+
+    my %letter_single_source;
+    for %letter_sources.kv -> Str $letter, @source_counts {
+        my @indexes = @source_counts.pairs.grep(*.value.defined)».key;
+        %letter_single_source{$letter} = @indexes.head if @indexes == 1;
+    }
+
+    my UInt    $stickers_bought = 0;
+    my BagHash $bought_unused_letters;
+    sub buy ( UInt $index --> Nil ) {
+        my Bag $b = @sticker_letters[$index]
+            orelse die "Cannot happen";
+        $bought_unused_letters{$_} += $b{$_} for $b.keys;
+        $stickers_bought++;
+    }
+
+    sub use_up_all ( --> Nil ) {
+        for $bought_unused_letters.kv -> Str $letter, UInt $have {
+            my UInt $need  = $word_letters{$letter}
+                or next;
+            my UInt $using = [min] $have, $need;
+
+            $bought_unused_letters{$letter} -= $using;
+            $word_letters{         $letter} -= $using;
+        }
+    }
+
+    sub buy_all_single_source_stickers ( --> Nil ) {
+        loop {
+            my $letter = $word_letters.keys.sort.first({ %letter_single_source{$_}.defined })
+                orelse return;
+
+            my $index  = %letter_single_source{$letter};
+            buy( $index );
+            use_up_all();
+        }
+    }
+    buy_all_single_source_stickers();
+
+    return $stickers_bought if not $word_letters;
+
+    # Past this point, the problem deserves a better algorithm.
+    # At the very least, I should run an analysis to allow selecting `$target_letter`
+    # based on count of stickers needed instead of count of letters needed.
+    # However, I am out of time for this week.
+    warn "The answer you are about to get might not be the minimum possible";
+
+    # At this point, all remaining letters have multiple sources.
+    while $word_letters {
+        my ($target_letter, $target_count) = $word_letters.max(*.value).kv;
+        my ($next_sticker_index, $next_sticker_letter_count) = %letter_sources{$target_letter}.pairs.max({.value // 0}).kv;
+        my $quantity_to_buy = ( $target_count / $next_sticker_letter_count ).ceiling;
+        buy($next_sticker_index) for ^$quantity_to_buy;
+        use_up_all();
+    }
+
+    return $stickers_bought;
+}
+
+my @tests =
+    ( <perl raku    python> , 'peon'          , 2 ),
+    ( <love hate    angry>  , 'goat'          , 3 ),
+    ( <come nation  delta>  , 'accommodation' , 4 ),
+    ( <come country delta>  , 'accommodation' , 0 ),
+
+    ( <come nation  delta>  , 'accommodationoooooooooooo' , 16 ),
+;
+use Test;
+plan +@tests;
+for @tests -> ( $in_stickers, $in_word, $expected ) {
+    is    task2($in_stickers, $in_word),$expected;
+}