Merge pull request #10558 from Firedrake/rogerbw-challenge-281

RogerBW solutions for challenge no. 281

23 files changed, 1050 insertions, 0 deletions

diff --git a/challenge-281/roger-bell-west/crystal/ch-1.cr b/challenge-281/roger-bell-west/crystal/ch-1.cr
new file mode 100755
index 0000000000..e8f0745b2a
--- /dev/null
+++ b/challenge-281/roger-bell-west/crystal/ch-1.cr
@@ -0,0 +1,25 @@
+#! /usr/bin/crystal
+require "spec"
+describe "checkcolor" do
+  it "test_ex1" do
+    checkcolor("d3").should eq true
+  end
+  it "test_ex2" do
+    checkcolor("g5").should eq false
+  end
+  it "test_ex3" do
+    checkcolor("e6").should eq true
+  end
+end
+
+def cs2xy(a)
+  c = a.chars
+  x = c[0].ord - 'a'.ord
+  y = c[1].ord - '1'.ord
+  [x, y]
+end
+
+def checkcolor(a)
+  xy = cs2xy(a)
+  (xy[0] + xy[1]) % 2 == 1
+end
diff --git a/challenge-281/roger-bell-west/crystal/ch-2.cr b/challenge-281/roger-bell-west/crystal/ch-2.cr
new file mode 100755
index 0000000000..077af477a4
--- /dev/null
+++ b/challenge-281/roger-bell-west/crystal/ch-2.cr
@@ -0,0 +1,52 @@
+#! /usr/bin/crystal
+require "spec"
+describe "knightsmove" do
+  it "test_ex1" do
+    knightsmove("g2", "a8").should eq 4
+  end
+  it "test_ex2" do
+    knightsmove("g2", "h2").should eq 3
+  end
+end
+
+def cs2xy(a)
+  c = a.chars
+  x = c[0].ord - 'a'.ord
+  y = c[1].ord - '1'.ord
+  [x, y]
+end
+
+def knightsmove(from, to)
+  fc = cs2xy(from)
+  tc = cs2xy(to)
+  queue = Deque(Array(Int32)).new
+  queue.push([fc[0], fc[1], 0])
+  seen = Set(Array(Int32)).new
+  while queue.size > 0
+    cc = queue.shift
+    if cc[0] == tc[0] && cc[1] == tc[1]
+      return cc[2]
+    else
+      [
+        [2, 1],
+        [1, 2],
+        [2, -1],
+        [1, -2],
+        [-2, 1],
+        [-1, 2],
+        [-2, -1],
+        [-1, -2],
+      ].each do |offset|
+        x = cc[0] + offset[0]
+        y = cc[1] + offset[1]
+        if x >= 0 && x <= 7 && y >= 0 && y <= 7
+          if !seen.includes?([x, y])
+            queue.push([x, y, cc[2] + 1])
+            seen.add([x, y])
+          end
+        end
+      end
+    end
+  end
+  -1
+end
diff --git a/challenge-281/roger-bell-west/javascript/ch-1.js b/challenge-281/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..d07544d416
--- /dev/null
+++ b/challenge-281/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,33 @@
+#! /usr/bin/node
+
+"use strict"
+
+function cs2xy(a) {
+    const x = a.charCodeAt(0) - 'a'.charCodeAt(0);
+    const y = a.charCodeAt(1) - '1'.charCodeAt(0);
+    return [x, y];
+}
+
+function checkcolor(a) {
+    const xy = cs2xy(a);
+    return (xy[0] + xy[1]) % 2 == 1;
+}
+
+if (checkcolor('d3')) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (!checkcolor('g5')) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (checkcolor('e6')) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-281/roger-bell-west/javascript/ch-2.js b/challenge-281/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..d14b70c0b6
--- /dev/null
+++ b/challenge-281/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,58 @@
+#! /usr/bin/node
+
+"use strict"
+
+function cs2xy(a) {
+    const x = a.charCodeAt(0) - 'a'.charCodeAt(0);
+    const y = a.charCodeAt(1) - '1'.charCodeAt(0);
+    return [x, y];
+}
+
+function knightsmove(from, to) {
+    const fc = cs2xy(from);
+    const tc = cs2xy(to);
+    let queue = [];
+    queue.push([fc[0], fc[1], 0]);
+    let seen = new Set;
+    while (queue.length > 0) {
+        const cc = queue.shift();
+        if (cc[0] == tc[0] && cc[1] == tc[1]) {
+            return cc[2];
+        } else {
+            for (let offset of [
+                [2, 1],
+                [1, 2],
+                [2, -1],
+                [1, -2],
+                [-2, 1],
+                [-1, 2],
+                [-2, -1],
+                [-1, -2]
+            ]) {
+                const x = cc[0] + offset[0];
+                const y = cc[1] + offset[1];
+                if (x >= 0 && x <= 7 && y >= 0 && y <= 7) {
+                    const cv = x * 8 + y;
+                    if (!seen.has(cv)) {
+                        queue.push([x, y, cc[2] + 1]);
+                        seen.add(cv);
+                    }
+                }
+            }
+        }
+    }
+    return -1;
+}
+
+if (knightsmove('g2', 'a8') == 4) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (knightsmove('g2', 'h2') == 3) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-281/roger-bell-west/kotlin/ch-1.kt b/challenge-281/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..2f71eaf7be
--- /dev/null
+++ b/challenge-281/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,34 @@
+fun cs2xy(a: String): Pair<Int, Int> {
+    val c = a.toList()
+    val x = c[0].code - 'a'.code
+    val y = c[1].code - '1'.code
+    return Pair(x, y)
+}
+
+fun checkcolor(a: String): Boolean {
+    val xy = cs2xy(a)
+    return (xy.first + xy.second) % 2 == 1
+}
+
+fun main() {
+
+    if (checkcolor("d3")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (!checkcolor("g5")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (checkcolor("e6")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-281/roger-bell-west/kotlin/ch-2.kt b/challenge-281/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..203a2dd4e5
--- /dev/null
+++ b/challenge-281/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,59 @@
+fun cs2xy(a: String): Pair<Int, Int> {
+    val c = a.toList()
+    val x = c[0].code - 'a'.code
+    val y = c[1].code - '1'.code
+    return Pair(x, y)
+}
+
+fun knightsmove(from: String, to: String): Int {
+    val fc = cs2xy(from)
+    val tc = cs2xy(to)
+    var queue = ArrayDeque<List<Int>>()
+    queue.add(listOf(fc.first, fc.second, 0))
+    var seen = mutableSetOf<Int>()
+    while (queue.size > 0) {
+        val cc = queue.removeFirst()
+        if (cc[0] == tc.first && cc[1] == tc.second) {
+            return cc[2]
+        } else {
+            for (offset in listOf (
+                     listOf(2, 1),
+                     listOf(1, 2),
+                     listOf(2, -1),
+                     listOf(1, -2),
+                     listOf(-2, 1),
+                     listOf(-1, 2),
+                     listOf(-2, -1),
+                     listOf(-1, -2)
+            )) {
+                val x = cc[0] + offset[0]
+                val y = cc[1] + offset[1]
+                if (x >= 0 && x <= 7 && y >= 0 && y <= 7) {
+                    val cv = x * 8 + y
+                    if (!seen.contains(cv)) {
+                        queue.add(listOf(x, y, cc[2] + 1))
+                        seen.add(cv)
+                    }
+                }
+            }
+        }
+    }
+    return -1
+}
+
+fun main() {
+
+    if (knightsmove("g2", "a8") == 4) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (knightsmove("g2", "h2") == 3) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-281/roger-bell-west/lua/ch-1.lua b/challenge-281/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..afb6fa324b
--- /dev/null
+++ b/challenge-281/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,34 @@
+#! /usr/bin/lua
+
+function cs2xy(a)
+   local x = string.byte(a, 1) - string.byte("a")
+   local y = string.byte(a, 2) - string.byte("1")
+   return {x, y}
+end
+
+function checkcolor(a)
+   local xy = cs2xy(a)
+   return (xy[1] + xy[2]) % 2 == 1
+end
+
+if checkcolor("d3") then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if not checkcolor("g5") then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if checkcolor("e6") then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-281/roger-bell-west/lua/ch-2.lua b/challenge-281/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..3979fb2830
--- /dev/null
+++ b/challenge-281/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,58 @@
+#! /usr/bin/lua
+
+function cs2xy(a)
+   local x = string.byte(a, 1) - string.byte("a")
+   local y = string.byte(a, 2) - string.byte("1")
+   return {x, y}
+end
+
+function knightsmove(from, to)
+   local fc = cs2xy(from)
+   local tc = cs2xy(to)
+   local queue = {}
+   table.insert(queue, {fc[1], fc[2], 0})
+   local seen = {}
+   while #queue > 0 do
+      local cc = table.remove(queue, 1)
+      if (cc[1] == tc[1] and cc[2] == tc[2]) then
+         return cc[3]
+      else
+         for _, offset in ipairs({
+               {2, 1},
+               {1, 2},
+               {2, -1},
+               {1, -2},
+               {-2, 1},
+               {-1, 2},
+               {-2, -1},
+               {-1, -2}
+         }) do
+            local x = cc[1] + offset[1]
+            local y = cc[2] + offset[2]
+            if (x >= 0 and x <= 7 and y >= 0 and y <= 7) then
+               local cv = x * 8 + y
+               if seen[cv] == nil then
+                  table.insert(queue, {x, y, cc[3] + 1})
+                  seen[cv] = true
+               end
+            end
+         end
+      end
+   end
+   return -1
+end
+
+if knightsmove("g2", "a8") == 4 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if knightsmove("g2", "h2") == 3 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-281/roger-bell-west/perl/ch-1.pl b/challenge-281/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..f9acac4da2
--- /dev/null
+++ b/challenge-281/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,23 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 3;
+
+is(checkcolor('d3'), 1, 'example 1');
+is(checkcolor('g5'), 0, 'example 2');
+is(checkcolor('e6'), 1, 'example 3');
+
+sub cs2xy($a) {
+  my @c = split('', $a);
+  my $x = ord($c[0]) - ord('a');
+  my $y = ord($c[1]) - ord('1');
+  return [$x, $y];
+}
+
+sub checkcolor($a) {
+  my $xy = cs2xy($a);
+  return (($xy->[0] + $xy->[1]) % 2 == 1)?1:0;
+}
diff --git a/challenge-281/roger-bell-west/perl/ch-2.pl b/challenge-281/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..01b2fb0cbc
--- /dev/null
+++ b/challenge-281/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,53 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 2;
+
+is(knightsmove('g2', 'a8'), 4, 'example 1');
+is(knightsmove('g2', 'h2'), 3, 'example 2');
+
+sub cs2xy($a) {
+  my @c = split('', $a);
+  my $x = ord($c[0]) - ord('a');
+  my $y = ord($c[1]) - ord('1');
+  return [$x, $y];
+}
+
+sub knightsmove($from, $to) {
+  my $fc = cs2xy($from);
+  my $tc = cs2xy($to);
+  my @queue;
+  push @queue, [$fc->[0], $fc->[1], 0];
+  my %seen;
+  while (@queue) {
+    my $cc = shift @queue;
+    if ($cc->[0] == $tc->[0] && $cc->[1] == $tc->[1]) {
+      return $cc->[2];
+    } else {
+      foreach my $offset (
+        [2, 1],
+        [1, 2],
+        [2, -1],
+        [1, -2],
+        [-2, 1],
+        [-1, 2],
+        [-2, -1],
+        [-1, -2]
+          ) {
+        my $x = $cc->[0] + $offset->[0];
+        my $y = $cc->[1] + $offset->[1];
+        if ($x >= 0 && $x <= 7 && $y >= 0 && $y <= 7) {
+          my $cv = $x * 8 + $y;
+          if (!exists $seen{$cv}) {
+            push @queue,[$x, $y, $cc->[2] + 1];
+            $seen{$cv} = 1;
+          }
+        }
+      }
+    }
+  }
+  return -1;
+}
diff --git a/challenge-281/roger-bell-west/postscript/ch-1.ps b/challenge-281/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..f1b160ebc7
--- /dev/null
+++ b/challenge-281/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,62 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/test {
+    /test.count test.count 1 add def
+    {
+        /test.pass test.pass 1 add def
+    } {
+        ( ) print
+        test.count (....) cvs print
+        (-fail) print
+    } ifelse
+} bind def
+
+/test.end {
+    ( ) print
+    test.count 0 gt {
+        (Passed ) print
+        test.pass (...) cvs print
+        (/) print
+        test.count (...) cvs print
+        ( \() print
+        test.pass 100 mul test.count idiv (...) cvs print
+        (%\)) print
+        (\r\n) print
+    } if
+} bind def
+
+/s2a {
+    [ exch { } forall ]
+} bind def
+
+
+% end included library code
+
+/cs2xy {
+    [ exch
+      s2a aload pop
+      (1) s2a aload pop sub
+      exch
+      (a) s2a aload pop sub
+      exch
+    ]
+} bind def
+
+/checkcolor {
+    cs2xy aload pop
+    add 2 mod 1 eq
+} bind def
+
+(checkcolor) test.start
+(d3) checkcolor test
+(g5) checkcolor not test
+(e6) checkcolor test
+test.end
diff --git a/challenge-281/roger-bell-west/postscript/ch-2.ps b/challenge-281/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..6f78ee73d3
--- /dev/null
+++ b/challenge-281/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,109 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/s2a {
+    [ exch { } forall ]
+} bind def
+
+/test {
+    /test.count test.count 1 add def
+    {
+        /test.pass test.pass 1 add def
+    } {
+        ( ) print
+        test.count (....) cvs print
+        (-fail) print
+    } ifelse
+} bind def
+
+/apush.right { % [a b] c -> [a b c]
+    exch
+    [ exch aload length 2 add -1 roll ]
+} bind def
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/test.end {
+    ( ) print
+    test.count 0 gt {
+        (Passed ) print
+        test.pass (...) cvs print
+        (/) print
+        test.count (...) cvs print
+        ( \() print
+        test.pass 100 mul test.count idiv (...) cvs print
+        (%\)) print
+        (\r\n) print
+    } if
+} bind def
+
+/apop.left { % [a b c] -> [b c] a
+    dup 0 get exch
+    [ exch aload length -1 roll pop ] exch
+} bind def
+
+
+% end included library code
+
+/cs2xy {
+    [ exch
+      s2a aload pop
+      (1) s2a aload pop sub
+      exch
+      (a) s2a aload pop sub
+      exch
+    ]
+} bind def
+
+/knightsmove {
+    0 dict begin
+    cs2xy /tc exch def
+    cs2xy /fc exch def
+    /queue [ [ fc 0 get fc 1 get 0 ] ] def
+    /seen 0 dict def
+    -1
+    {
+        queue length 1 ge {
+            queue apop.left /cc exch def /queue exch def
+            cc 0 get tc 0 get eq cc 1 get tc 1 get eq and {
+                pop cc 2 get
+                exit
+            } {
+                [
+                    [2 1]
+                    [1 2]
+                    [2 -1]
+                    [1 -2]
+                    [-2 1]
+                    [-1 2]
+                    [-2 -1]
+                    [-1 -2]
+                ] {
+                    /offset exch def
+                    /x cc 0 get offset 0 get add def
+                    /y cc 1 get offset 1 get add def
+                    x 0 ge x 7 le and y 0 ge and y 7 le and {
+                        /cv x 8 mul y add def
+                        seen cv known not {
+                            /queue queue [ x y cc 2 get 1 add ] apush.right def
+                            seen cv true put
+                        } if
+                    } if
+                } forall
+            } ifelse
+        } {
+            exit
+        } ifelse
+    } loop
+    end
+} bind def
+
+(knightsmove) test.start
+(g2) (a8) knightsmove 4 eq test
+(g2) (h2) knightsmove 3 eq test
+test.end
diff --git a/challenge-281/roger-bell-west/python/ch-1.py b/challenge-281/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..fb683db3ea
--- /dev/null
+++ b/challenge-281/roger-bell-west/python/ch-1.py
@@ -0,0 +1,25 @@
+#! /usr/bin/python3
+
+def cs2xy(a):
+  x = ord(a[0]) - ord('a')
+  y = ord(a[1]) - ord('1')
+  return [x, y]
+
+def checkcolor(a):
+  xy = cs2xy(a)
+  return (xy[0] + xy[1]) % 2 == 1
+
+import unittest
+
+class TestCheckcolor(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(checkcolor("d3"), True, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(checkcolor("g5"), False, 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(checkcolor("e6"), True, 'example 3')
+
+unittest.main()
diff --git a/challenge-281/roger-bell-west/python/ch-2.py b/challenge-281/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..e6bbe85da8
--- /dev/null
+++ b/challenge-281/roger-bell-west/python/ch-2.py
@@ -0,0 +1,41 @@
+#! /usr/bin/python3
+
+from collections import deque
+
+def cs2xy(a):
+  x = ord(a[0]) - ord('a')
+  y = ord(a[1]) - ord('1')
+  return [x, y]
+
+def knightsmove(ffrom, to):
+  fc = cs2xy(ffrom)
+  tc = cs2xy(to)
+  queue = deque()
+  queue.append((fc[0], fc[1], 0))
+  seen = set()
+  while len(queue) > 0:
+    cc = queue.popleft()
+    if cc[0] == tc[0] and cc[1] == tc[1]:
+      return cc[2]
+    else:
+      for offset in ( (2, 1), (1, 2), (2, -1), (1, -2), (-2, 1), (-1, 2), (-2, -1), (-1, -2) ):
+        x = cc[0] + offset[0]
+        y = cc[1] + offset[1]
+        if x >= 0 and x <= 7 and y >= 0 and y <= 7:
+          cv = x * 8 + y
+          if cv not in seen:
+            queue.append((x, y, cc[2] + 1))
+            seen.add(cv)
+  return -1
+
+import unittest
+
+class TestKnightsmove(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(knightsmove("g2", "a8"), 4, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(knightsmove("g2", "h2"), 3, 'example 2')
+
+unittest.main()
diff --git a/challenge-281/roger-bell-west/raku/ch-1.p6 b/challenge-281/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..bca1ffd049
--- /dev/null
+++ b/challenge-281/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,21 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 3;
+
+is(checkcolor('d3'), True, 'example 1');
+is(checkcolor('g5'), False, 'example 2');
+is(checkcolor('e6'), True, 'example 3');
+
+sub cs2xy($a) {
+  my @c = $a.comb;
+  my $x = ord(@c[0]) - ord('a');
+  my $y = ord(@c[1]) - ord('1');
+  return [$x, $y];
+}
+
+sub checkcolor($a) {
+  my @xy = cs2xy($a);
+  return (@xy[0] + @xy[1]) % 2 == 1;
+}
diff --git a/challenge-281/roger-bell-west/raku/ch-2.p6 b/challenge-281/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..6cf2e65ae6
--- /dev/null
+++ b/challenge-281/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,51 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 2;
+
+is(knightsmove('g2', 'a8'), 4, 'example 1');
+is(knightsmove('g2', 'h2'), 3, 'example 2');
+
+sub cs2xy($a) {
+  my @c = $a.comb;
+  my $x = ord(@c[0]) - ord('a');
+  my $y = ord(@c[1]) - ord('1');
+  return [$x, $y];
+}
+
+sub knightsmove($from, $to) {
+    my @fc = cs2xy($from);
+    my @tc = cs2xy($to);
+    my @queue;
+    @queue.push([@fc[0], @fc[1], 0]);
+    my %seen = SetHash.new;
+    while (@queue.elems > 0) {
+        my @cc = @queue.shift.flat;
+        if (@cc[0] == @tc[0] && @cc[1] == @tc[1]) {
+            return @cc[2];
+        } else {
+            for (
+                [2, 1],
+                [1, 2],
+                [2, -1],
+                [1, -2],
+                [-2, 1],
+                [-1, 2],
+                [-2, -1],
+                [-1, -2]
+            ) -> @offset {
+                my $x = @cc[0] + @offset[0];
+                my $y = @cc[1] + @offset[1];
+                if ($x >= 0 && $x <= 7 && $y >= 0 && $y <= 7) {
+                    my $cv = $x * 8 + $y;
+                    if (%seen{$cv}:!exists) {
+                        @queue.push([$x, $y, @cc[2] + 1]);
+                        %seen{$cv} = True;
+                    }
+                }
+            }
+        }
+    }
+    return -1;
+}
diff --git a/challenge-281/roger-bell-west/ruby/ch-1.rb b/challenge-281/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..745f286ba4
--- /dev/null
+++ b/challenge-281/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,31 @@
+#! /usr/bin/ruby
+
+def cs2xy(a)
+  c = a.chars
+  x = c[0].ord - 'a'.ord
+  y = c[1].ord - '1'.ord
+  [x, y]
+end
+
+def checkcolor(a)
+  xy = cs2xy(a)
+  (xy[0] + xy[1]) % 2 == 1
+end
+
+require 'test/unit'
+
+class TestCheckcolor < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(true, checkcolor('d3'))
+  end
+
+  def test_ex2
+    assert_equal(false, checkcolor('g5'))
+  end
+
+  def test_ex3
+    assert_equal(true, checkcolor('e6'))
+  end
+
+end
diff --git a/challenge-281/roger-bell-west/ruby/ch-2.rb b/challenge-281/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..fa48d3d65a
--- /dev/null
+++ b/challenge-281/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,59 @@
+#! /usr/bin/ruby
+
+require 'set'
+
+def cs2xy(a)
+  c = a.chars
+  x = c[0].ord - 'a'.ord
+  y = c[1].ord - '1'.ord
+  [x, y]
+end
+
+def knightsmove(from, to)
+  fc = cs2xy(from)
+  tc = cs2xy(to)
+  queue = Array.new
+  queue.push([fc[0], fc[1], 0])
+  seen = Set.new
+  while queue.size > 0
+    cc = queue.shift
+    if cc[0] == tc[0] && cc[1] == tc[1]
+      return cc[2]
+    else
+      [
+        [2, 1],
+        [1, 2],
+        [2, -1],
+        [1, -2],
+        [-2, 1],
+        [-1, 2],
+        [-2, -1],
+        [-1, -2],
+      ].each do |offset|
+        x = cc[0] + offset[0]
+        y = cc[1] + offset[1]
+        if x >= 0 && x <= 7 && y >= 0 && y <= 7
+          if !seen.include?([x, y])
+            queue.push([x, y, cc[2] + 1])
+            seen.add([x, y])
+          end
+        end
+      end
+    end
+  end
+  -1
+end
+
+require 'test/unit'
+
+class TestKnightsmove < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(4, knightsmove('g2', 'a8'))
+  end
+
+  def test_ex2
+    assert_equal(3, knightsmove('g2', 'h2'))
+  end
+
+end
diff --git a/challenge-281/roger-bell-west/rust/ch-1.rs b/challenge-281/roger-bell-west/rust/ch-1.rs
new file mode 100755
index 0000000000..17e7af026c
--- /dev/null
+++ b/challenge-281/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,29 @@
+#! /bin/sh
+//usr/bin/env rustc --test $0 -o ${0}x && ./${0}x --nocapture; rm -f ${0}x ; exit
+
+#[test]
+fn test_ex1() {
+    assert_eq!(checkcolor("d3"), true);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(checkcolor("g5"), false);
+}
+
+#[test]
+fn test_ex3() {
+    assert_eq!(checkcolor("e6"), true);
+}
+
+fn cs2xy(a: &str) -> (u8, u8) {
+    let c = a.chars().collect::<Vec<char>>();
+    let x = c[0] as u8 - 'a' as u8;
+    let y = c[1] as u8 - '1' as u8;
+    (x, y)
+}
+
+fn checkcolor(a: &str) -> bool {
+    let xy = cs2xy(a);
+    (xy.0 + xy.1) % 2 == 1
+}
diff --git a/challenge-281/roger-bell-west/rust/ch-2.rs b/challenge-281/roger-bell-west/rust/ch-2.rs
new file mode 100755
index 0000000000..14f213dc54
--- /dev/null
+++ b/challenge-281/roger-bell-west/rust/ch-2.rs
@@ -0,0 +1,55 @@
+#! /bin/sh
+//usr/bin/env rustc --test $0 -o ${0}x && ./${0}x --nocapture; rm -f ${0}x ; exit
+
+use std::collections::{HashSet, VecDeque};
+
+#[test]
+fn test_ex1() {
+    assert_eq!(knightsmove("g2", "a8"), 4);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(knightsmove("g2", "h2"), 3);
+}
+
+fn cs2xy(a: &str) -> (i8, i8) {
+    let c = a.chars().collect::<Vec<char>>();
+    let x = c[0] as i8 - 'a' as i8;
+    let y = c[1] as i8 - '1' as i8;
+    (x, y)
+}
+
+fn knightsmove(from: &str, to: &str) -> isize {
+    let fc = cs2xy(from);
+    let tc = cs2xy(to);
+    let mut queue: VecDeque<(i8, i8, isize)> = VecDeque::new();