From d0082a9da8758301e2d7b59cc30b74f30d97f979 Mon Sep 17 00:00:00 2001
From: Jan Krňávek <Jan.Krnavek@gmail.com>
Date: Mon, 5 Aug 2024 19:35:26 +0200
Subject: solutions week 281

---
 challenge-281/wambash/raku/ch-1.raku | 21 +++++++++++++++
 challenge-281/wambash/raku/ch-2.raku | 50 ++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)
 create mode 100644 challenge-281/wambash/raku/ch-1.raku
 create mode 100644 challenge-281/wambash/raku/ch-2.raku

diff --git a/challenge-281/wambash/raku/ch-1.raku b/challenge-281/wambash/raku/ch-1.raku
new file mode 100644
index 0000000000..f6aa3c168c
--- /dev/null
+++ b/challenge-281/wambash/raku/ch-1.raku
@@ -0,0 +1,21 @@
+#!/usr/bin/env raku
+enum Col (<a>..<h>);
+
+sub check-color ($coordinates) {
+    $coordinates
+    andthen .comb
+    andthen Col::{.[0]} + .[1]
+    andthen $_ %% 2
+}
+
+multi MAIN (Bool :test($)!) {
+    use Test;
+    is check-color('d3'), True;
+    is check-color('g5'), False;
+    is check-color('e6'), True;
+    done-testing;
+}
+
+multi MAIN ($coordinates) {
+    say check-color $coordinates
+}
diff --git a/challenge-281/wambash/raku/ch-2.raku b/challenge-281/wambash/raku/ch-2.raku
new file mode 100644
index 0000000000..0d13f4fce5
--- /dev/null
+++ b/challenge-281/wambash/raku/ch-2.raku
@@ -0,0 +1,50 @@
+#!/usr/bin/env raku
+use v6.e.PREVIEW;
+use Graph;
+
+
+enum Col (<a>..<h>);
+enum Row (1=> 1, slip 2..8);
+
+constant @vertices = Col::.values.sort X, Row::.values.sort;
+
+sub move ( @ (Col $col, Row $row), @ ($col-diff,$row-diff) ) {
+    Col($col+$col-diff)//Nil, Row($row+$row-diff)//Nil
+    andthen  .all.defined ?? $_ !! Empty
+}
+
+sub knight-jump ( +@vertex (Col $, Row $) ) {
+     1 X, (-2, 2)
+    andthen .map: { slip $_, .reverse }\
+    andthen .map: &move.assuming(@vertex)\
+}
+
+constant @edges = (
+    @vertices
+    andthen .map: { slip $_.join X, knight-jump $_  }\
+    andthen .map: { %( from => .[0].join, to => .[1].join, weight => 1 ) }
+);
+
+constant knight-moves = Graph.new(
+    @edges
+);
+
+sub knight's-move ($start, $end) {
+    knight-moves.find-shortest-path: $start, $end
+    andthen .elems - 1
+}
+
+multi MAIN (Bool :test($)!) {
+    use Test;
+    is knight-jump( g, Row(2) ), ((e,Row(3)),(h,Row(4)),);
+    is knight-jump( c, Row(4) ), ((d,Row(2)),(a,Row(5)),(d,Row(6)),(e,Row(5)));
+    is knight's-move('g2','a8'), 4;
+    is knight's-move('g2','h2'), 3;
+    is knight's-move('g2','h4'), 1;
+    is knight's-move('g2','g6'), 2;
+    done-testing;
+}
+
+multi MAIN ($start, $end) {
+    say knight's-move $start, $end
+}
-- 
cgit 


From fb45c676a28e4d47d81cba82f273059f255de670 Mon Sep 17 00:00:00 2001
From: Jan Krňávek <Jan.Krnavek@gmail.com>
Date: Mon, 5 Aug 2024 19:40:27 +0200
Subject: try undefined enum

---
 challenge-281/wambash/raku/ch-2.raku | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/challenge-281/wambash/raku/ch-2.raku b/challenge-281/wambash/raku/ch-2.raku
index 0d13f4fce5..85cbe99c8b 100644
--- a/challenge-281/wambash/raku/ch-2.raku
+++ b/challenge-281/wambash/raku/ch-2.raku
@@ -9,8 +9,8 @@ enum Row (1=> 1, slip 2..8);
 constant @vertices = Col::.values.sort X, Row::.values.sort;
 
 sub move ( @ (Col $col, Row $row), @ ($col-diff,$row-diff) ) {
-    Col($col+$col-diff)//Nil, Row($row+$row-diff)//Nil
-    andthen  .all.defined ?? $_ !! Empty
+    try { Col($col+$col-diff), Row($row+$row-diff) }\
+    orelse Empty
 }
 
 sub knight-jump ( +@vertex (Col $, Row $) ) {
-- 
cgit 


From 1a09a37ffd076a2f5ba66eb55f4391851946ee27 Mon Sep 17 00:00:00 2001
From: Jan Krňávek <Jan.Krnavek@gmail.com>
Date: Mon, 5 Aug 2024 20:01:29 +0200
Subject: direct making adjacency-list

---
 challenge-281/wambash/raku/ch-2.raku | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/challenge-281/wambash/raku/ch-2.raku b/challenge-281/wambash/raku/ch-2.raku
index 85cbe99c8b..8a96934cd6 100644
--- a/challenge-281/wambash/raku/ch-2.raku
+++ b/challenge-281/wambash/raku/ch-2.raku
@@ -4,29 +4,27 @@ use Graph;
 
 
 enum Col (<a>..<h>);
-enum Row (1=> 1, slip 2..8);
+enum Row (1 => 1, slip 2..8);
 
 constant @vertices = Col::.values.sort X, Row::.values.sort;
 
 sub move ( @ (Col $col, Row $row), @ ($col-diff,$row-diff) ) {
-    try { Col($col+$col-diff), Row($row+$row-diff) }\
+    try { Col($col+$col-diff), Row($row+$row-diff) }\ 
     orelse Empty
 }
 
 sub knight-jump ( +@vertex (Col $, Row $) ) {
-     1 X, (-2, 2)
+    -1, 1  X,  -2, 2
     andthen .map: { slip $_, .reverse }\
     andthen .map: &move.assuming(@vertex)\
 }
 
-constant @edges = (
-    @vertices
-    andthen .map: { slip $_.join X, knight-jump $_  }\
-    andthen .map: { %( from => .[0].join, to => .[1].join, weight => 1 ) }
+constant %adjacency-list = %(
+    @vertices.map: { $_.join => set knight-jump($_).map: *.join  }\
 );
 
 constant knight-moves = Graph.new(
-    @edges
+    :%adjacency-list
 );
 
 sub knight's-move ($start, $end) {
@@ -36,8 +34,8 @@ sub knight's-move ($start, $end) {
 
 multi MAIN (Bool :test($)!) {
     use Test;
-    is knight-jump( g, Row(2) ), ((e,Row(3)),(h,Row(4)),);
-    is knight-jump( c, Row(4) ), ((d,Row(2)),(a,Row(5)),(d,Row(6)),(e,Row(5)));
+    is knight-jump( g, Row(2) ), ((e,Row(1)),(f,Row(4)),(e,Row(3)),(h,Row(4)),);
+    is knight-jump( c, Row(4) ), ((b,Row(2)),(a,Row(3)),(b,Row(6)),(e,Row(3)),(d,Row(2)),(a,Row(5)),(d,Row(6)),(e,Row(5)));
     is knight's-move('g2','a8'), 4;
     is knight's-move('g2','h2'), 3;
     is knight's-move('g2','h4'), 1;
-- 
cgit