From 94790f02a8df556d6ebf09d9225e44f2505039d7 Mon Sep 17 00:00:00 2001
From: Noud Aldenhoven <noud.aldenhoven@gmail.com>
Date: Sat, 11 Jul 2020 15:56:13 +0200
Subject: Solution to challenge 68 task 1 and 2 in Raku by Noud

---
 challenge-068/noud/raku/ch-1.p6 | 59 ++++++++++++++++++++++++++++++++++
 challenge-068/noud/raku/ch-2.p6 | 71 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 challenge-068/noud/raku/ch-1.p6
 create mode 100644 challenge-068/noud/raku/ch-2.p6

diff --git a/challenge-068/noud/raku/ch-1.p6 b/challenge-068/noud/raku/ch-1.p6
new file mode 100644
index 0000000000..c75cd4f5f8
--- /dev/null
+++ b/challenge-068/noud/raku/ch-1.p6
@@ -0,0 +1,59 @@
+# You are given a matrix of size M x N having only 0s and 1s.
+#
+# Write a script to set the entire row and column to 0 if an element is 0.
+# Example 1
+#
+# Input: [1, 0, 1]
+#        [1, 1, 1]
+#        [1, 1, 1]
+#
+# Output: [0, 0, 0]
+#         [1, 0, 1]
+#         [1, 0, 1]
+#
+# Example 2
+#
+# Input: [1, 0, 1]
+#        [1, 1, 1]
+#        [1, 0, 1]
+#
+# Output: [0, 0, 0]
+#         [1, 0, 1]
+#         [0, 0, 0]
+#
+
+my @matrix1 = [
+    [1, 0, 1],
+    [1, 1, 1],
+    [1, 1, 1]
+];
+
+my @matrix2 = [
+    [1, 0, 1],
+    [1, 1, 1],
+    [1, 0, 1]
+];
+
+sub zero-matrix(@matrix, $m, $n) {
+    my @zero-entries = [];
+    for ^$m X ^$n -> ($i, $j) {
+        if (@matrix[$i][$j] == 0) {
+            @zero-entries.push([$i, $j]);
+        }
+    }
+
+    for @zero-entries -> ($i, $j) {
+        for ^$m -> $k {
+            @matrix[$k][$j] = 0;
+        }
+        for ^$n -> $l {
+            @matrix[$i][$l] = 0;
+        }
+    }
+
+    return @matrix;
+}
+
+.say for zero-matrix(@matrix1, 3, 3);
+say '';
+.say for zero-matrix(@matrix2, 3, 3);
diff --git a/challenge-068/noud/raku/ch-2.p6 b/challenge-068/noud/raku/ch-2.p6
new file mode 100644
index 0000000000..7258617954
--- /dev/null
+++ b/challenge-068/noud/raku/ch-2.p6
@@ -0,0 +1,71 @@
+# You are given a singly linked list $L as below:
+#
+# L0 →  L1 →  … →  Ln-1 →  Ln
+#
+# Write a script to reorder list as below:
+#
+# L0 →  Ln →  L1 →  Ln-1 →  L2 →  Ln-2 →
+#
+# You are ONLY allowed to do this in-place without altering the nodes’ values.
+# Example
+#
+# Input:  1 →  2 →  3 →  4
+# Output: 1 →  4 →  2 →  3
+#
+
+class Node {
+    has Int $.value is rw;
+    has Node $.next is rw;
+}
+
+class LinkedList {
+    has Node $.head is rw;
+
+    method create-list(@values) {
+        my $cur-node = $!head;
+
+        for @values -> $v {
+            my $new-node = Node.new(value => $v);
+            if ($cur-node) {
+                $cur-node.next = $new-node;
+            } else {
+                $!head = $new-node;
+            }
+            $cur-node = $new-node;
+        }
+    }
+
+    method print-list() {
+        my $cur-node = $!head;
+        my @values = [];
+        while ($cur-node) {
+            @values.push($cur-node.value);
+            $cur-node = $cur-node.next;
+        }
+        say @values.join(' -> ');
+    }
+
+    method reorder-list() {
+        my $cur-node = $!head;
+        while ($cur-node.next and $cur-node.next.next) {
+            my $one-but-last-node = $cur-node;
+            my $last-node = $cur-node.next;
+
+            while ($last-node.next) {
+                $one-but-last-node = $last-node;
+                $last-node = $last-node.next;
+            }
+
+            $last-node.next = $cur-node.next;
+            $cur-node.next = $last-node;
+            $one-but-last-node.next = Nil;
+            $cur-node = $last-node.next;
+        }
+    }
+}
+
+my $linked-list = LinkedList.new();
+$linked-list.create-list([1, 2, 3, 4, 5, 6, 7, 8]);
+$linked-list.print-list();
+$linked-list.reorder-list();
+$linked-list.print-list();
-- 
cgit