RogerBW solutions for challenge no. 321

25 files changed, 1025 insertions, 0 deletions

diff --git a/challenge-321/roger-bell-west/crystal/ch-1.cr b/challenge-321/roger-bell-west/crystal/ch-1.cr
new file mode 100755
index 0000000000..6b6a947474
--- /dev/null
+++ b/challenge-321/roger-bell-west/crystal/ch-1.cr
@@ -0,0 +1,24 @@
+#! /usr/bin/crystal
+
+def distinctaverage(a0)
+  a = a0.sort
+  offset = a.size - 1
+  res = Set(Int32).new
+  0.upto(a.size / 2 - 1) do |i|
+    res.add(a[i] + a[offset - i])
+  end
+  res.size
+end
+
+require "spec"
+describe "distinctaverage" do
+  it "test_ex1" do
+    distinctaverage([1, 2, 4, 3, 5, 6]).should eq 1
+  end
+  it "test_ex2" do
+    distinctaverage([0, 2, 4, 8, 3, 5]).should eq 2
+  end
+  it "test_ex3" do
+    distinctaverage([7, 3, 1, 0, 5, 9]).should eq 2
+  end
+end
diff --git a/challenge-321/roger-bell-west/crystal/ch-2.cr b/challenge-321/roger-bell-west/crystal/ch-2.cr
new file mode 100755
index 0000000000..2797e896d0
--- /dev/null
+++ b/challenge-321/roger-bell-west/crystal/ch-2.cr
@@ -0,0 +1,30 @@
+#! /usr/bin/crystal
+
+def backspacecompare(a, b)
+  sa = Array(String).new
+  [a, b].each do |i|
+    oa = Array(Char).new
+    i.chars.each do |c|
+      if c == '#'
+        oa.pop
+      else
+        oa.push(c)
+      end
+    end
+    sa.push(oa.join(""))
+  end
+  sa[0] == sa[1]
+end
+
+require "spec"
+describe "backspacecompare" do
+  it "test_ex1" do
+    backspacecompare("ab#c", "ad#c").should eq true
+  end
+  it "test_ex2" do
+    backspacecompare("ab##", "a#b#").should eq true
+  end
+  it "test_ex3" do
+    backspacecompare("a#b", "c").should eq false
+  end
+end
diff --git a/challenge-321/roger-bell-west/javascript/ch-1.js b/challenge-321/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..d6f078281e
--- /dev/null
+++ b/challenge-321/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,36 @@
+#! /usr/bin/node
+
+"use strict"
+
+function distinctaverage(a0) {
+    let a = [...a0];
+    a.sort(function(a,b) {
+        return a-b;
+    });
+    const offset = a.length - 1;
+    const limit = Math.floor(a.length / 2);
+    let res = new Set;
+    for (let i = 0; i < limit; i++) {
+        res.add(a[i] + a[offset - i]);
+    }
+    return res.size;
+}
+
+if (distinctaverage([1, 2, 4, 3, 5, 6]) == 1) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (distinctaverage([0, 2, 4, 8, 3, 5]) == 2) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (distinctaverage([7, 3, 1, 0, 5, 9]) == 2) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-321/roger-bell-west/javascript/ch-2.js b/challenge-321/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..1a58b683d0
--- /dev/null
+++ b/challenge-321/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,38 @@
+#! /usr/bin/node
+
+"use strict"
+
+function backspacecompare(a, b) {
+    let sa = [];
+    for (let i of [a, b]) {
+        let oa = [];
+        i.split("").forEach((c, _) => {
+            if (c == '#') {
+                oa.pop();
+            } else {
+                oa.push(c);
+            }
+        });
+        sa.push(oa.join(''));
+    }
+    return sa[0] == sa[1];
+}
+
+if (backspacecompare('ab#c', 'ad#c')) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (backspacecompare('ab##', 'a#b#')) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (!backspacecompare('a#b', 'c')) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-321/roger-bell-west/kotlin/ch-1.kt b/challenge-321/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..639e145135
--- /dev/null
+++ b/challenge-321/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,33 @@
+fun distinctaverage(a0: List<Int>): Int {
+    val a = a0.sorted()
+    val offset = a.size - 1
+    val limit = a.size / 2
+    var res = mutableSetOf<Int>()
+    for (i in 0 .. limit - 1) {
+        res.add(a[i] + a[offset - i])
+    }
+    return res.size
+}
+
+fun main() {
+
+    if (distinctaverage(listOf(1, 2, 4, 3, 5, 6)) == 1) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (distinctaverage(listOf(0, 2, 4, 8, 3, 5)) == 2) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (distinctaverage(listOf(7, 3, 1, 0, 5, 9)) == 2) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-321/roger-bell-west/kotlin/ch-2.kt b/challenge-321/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..41f1d76487
--- /dev/null
+++ b/challenge-321/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,38 @@
+fun backspacecompare(a: String, b: String): Boolean {
+    var sa = ArrayList<String>()
+    for (i in listOf(a, b)) {
+        var oa = ArrayList<Char>()
+        i.toCharArray().forEach() {c ->
+            if (c == '#') {
+                oa.removeLast()
+            } else {
+                oa.add(c)
+            }
+        }
+        sa.add(oa.joinToString(""))
+    }
+    return sa[0] == sa[1]
+}
+
+fun main() {
+
+    if (backspacecompare("ab#c", "ad#c")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (backspacecompare("ab##", "a#b#")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (!backspacecompare("a#b", "c")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-321/roger-bell-west/lua/ch-1.lua b/challenge-321/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..1445c9ad90
--- /dev/null
+++ b/challenge-321/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,42 @@
+#! /usr/bin/lua
+
+function propersize(t)
+   local l=0
+   for k,v in pairs(t) do
+      l = l + 1
+   end
+   return l
+end
+
+function distinctaverage(a0)
+   local a = a0
+   table.sort(a,function (aa, bb) return aa < bb end)
+   local offset = #a + 1
+   local res = {}
+   for i = 1, #a / 2 do
+      res[a[i] + a[offset - i]] = true
+   end
+   return propersize(res)
+end
+
+if distinctaverage({1, 2, 4, 3, 5, 6}) == 1 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if distinctaverage({0, 2, 4, 8, 3, 5}) == 2 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if distinctaverage({7, 3, 1, 0, 5, 9}) == 2 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-321/roger-bell-west/lua/ch-2.lua b/challenge-321/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..60d4d80aa7
--- /dev/null
+++ b/challenge-321/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,58 @@
+#! /usr/bin/lua
+
+function split(t)
+   local cl = {}
+   string.gsub(t,
+               "(.)",
+               function(c)
+                  table.insert(cl, c)
+               end
+   )
+   return cl
+end
+
+function join(t)
+   local out=""
+   for i, v in ipairs(t) do
+      out = out .. v
+   end
+   return out
+end
+
+function backspacecompare(a, b)
+   local sa = {}
+   for _, i in ipairs({a, b}) do
+      local oa = {}
+      for _n, c in ipairs(split(i)) do
+         if c == "#" then
+            table.remove(oa, #oa)
+         else
+            table.insert(oa, c)
+         end
+      end
+      table.insert(sa, join(oa))
+   end
+   return sa[1] == sa[2]
+end
+
+if backspacecompare("ab#c", "ad#c") then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if backspacecompare("ab##", "a#b#") then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if not backspacecompare("a#b", "c") then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-321/roger-bell-west/perl/ch-1.pl b/challenge-321/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..7463ba8611
--- /dev/null
+++ b/challenge-321/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,21 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 3;
+
+is(distinctaverage([1, 2, 4, 3, 5, 6]), 1, 'example 1');
+is(distinctaverage([0, 2, 4, 8, 3, 5]), 2, 'example 2');
+is(distinctaverage([7, 3, 1, 0, 5, 9]), 2, 'example 3');
+
+sub distinctaverage($a0) {
+  my @a = sort { $::a <=> $::b }  @{$a0};
+  my $offset = scalar @a - 1;
+  my %res;
+  foreach my $i (0 .. (scalar @a) / 2) {
+    $res{$a[$i] + $a[$offset - $i]} = 1;
+  }
+  scalar keys %res;
+}
diff --git a/challenge-321/roger-bell-west/perl/ch-2.pl b/challenge-321/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..391a91eb6f
--- /dev/null
+++ b/challenge-321/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,27 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 3;
+
+is(backspacecompare('ab#c', 'ad#c'), 1, 'example 1');
+is(backspacecompare('ab##', 'a#b#'), 1, 'example 2');
+is(backspacecompare('a#b', 'c'), 0, 'example 3');
+
+sub backspacecompare($a, $b) {
+  my @sa;
+  foreach my $i ($a, $b) {
+    my @oa;
+    foreach my $c (split '', $i) {
+      if ($c eq '#') {
+        pop @oa;
+      } else {
+        push @oa, $c;
+      }
+    }
+    push @sa, join('', @oa);
+  }
+  ($sa[0] eq $sa[1])?1:0;
+}
diff --git a/challenge-321/roger-bell-west/postscript/ch-1.ps b/challenge-321/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..827ad4ffed
--- /dev/null
+++ b/challenge-321/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,153 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/quicksort.cmp {
+    2 copy
+    lt {
+        pop pop -1
+    } {
+        gt {
+            1
+        } {
+            0
+        } ifelse
+    } ifelse
+} bind def
+
+/quicksort.swap {
+    2 dict begin
+    /bi exch def
+    /ai exch def
+    arr ai get
+    arr bi get
+    arr exch ai exch put
+    arr exch bi exch put
+    end
+} 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
+
+/quicksort.partition {
+    3 dict begin
+    /pivot arr hi lo add 2 idiv get def
+    /i lo 1 sub def
+    /j hi 1 add def
+    {
+        {
+            /i i 1 add def
+            arr i get pivot cmp 0 ge {
+                exit
+            } if
+        } loop
+        {
+            /j j 1 sub def
+            arr j get pivot cmp 0 le {
+                exit
+            } if
+        } loop
+        i j ge {
+            j
+            exit
+        } if
+        i j quicksort.swap
+    } loop
+    end
+} bind def
+
+/quicksort.main { % lo hi -> (null)
+    3 dict begin
+    /hi exch def
+    /lo exch def
+    /xit false def
+    lo 0 lt {
+        /xit true def
+    } if
+    hi 0 lt {
+        /xit true def
+    } if
+    lo hi ge {
+        /xit true def
+    } if
+    xit not {
+        /p quicksort.partition def
+        lo p quicksort.main
+        p 1 add hi quicksort.main
+    } if
+    end
+} bind def
+
+/quicksort {
+    { quicksort.cmp } quicksort.with_comparator
+} bind def
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/quicksort.with_comparator { % [ a c b ] { comparator } -> [ a b c ]
+    2 dict begin
+    /cmp exch def
+    /arr exch def
+    arr length 0 gt {
+        0 arr length 1 sub quicksort.main
+    } if
+    arr
+    end
+} bind def
+
+/keys { % dict -> array of dict keys
+    [ exch
+      {
+          pop
+      } 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
+
+
+% end included library code
+
+/distinctaverage {
+    0 dict begin
+    quicksort
+    /a exch def
+    /offset a length 1 sub def
+    /res 0 dict def
+    0 1 a length 2 idiv 1 sub {
+        /i exch def
+        res a i get a offset i sub get add true put
+    } for
+    res keys length
+    end
+} bind def
+
+(distinctaverage) test.start
+[1 2 4 3 5 6] distinctaverage 1 eq test
+[0 2 4 8 3 5] distinctaverage 2 eq test
+[7 3 1 0 5 9] distinctaverage 2 eq test
+test.end
diff --git a/challenge-321/roger-bell-west/postscript/ch-2.ps b/challenge-321/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..992dc0afb0
--- /dev/null
+++ b/challenge-321/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,120 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/s2a {
+    [ exch { } forall ]
+} 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
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/deepeq {
+    2 dict begin
+    /a exch def
+    /b exch def
+    a type b type eq {
+        a type /dicttype eq {
+            a length b length eq {
+                <<
+                    a {
+                        pop
+                        true
+                    } forall
+                    b {
+                        pop
+                        true
+                    } forall
+                >>
+                true exch
+                {
+                    pop
+                    dup a exch known {
+                        dup b exch known {
+                            dup a exch get exch b exch get deepeq not {
+                                pop false
+                            } if
+                        } {
+                            false
+                        } ifelse
+                    } {
+                        false
+                    } ifelse
+                } forall
+            } {
+                false
+            } ifelse
+        } {
+            a type dup /arraytype eq exch /stringtype eq or {
+                a length b length eq {
+                    true
+                    0 1 a length 1 sub {
+                        dup a exch get exch b exch get deepeq not {
+                            pop false
+                            exit
+                        } if
+                    } for
+                } {
+                    false
+                } ifelse
+            } {
+                a b eq
+            } ifelse
+        } ifelse
+    } {
+        false
+    } ifelse
+    end
+} 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
+
+
+% end included library code
+
+/backspacecompare {
+    2 array astore
+    {
+        [ exch
+          s2a {
+              dup
+              35 eq {
+                  pop pop
+              } if
+          } forall
+        ]
+    } forall
+    deepeq
+} bind def
+
+(backspacecompare) test.start
+(ab#c) (ad#c) backspacecompare test
+(ab##) (a#b#) backspacecompare test
+(a#b) (c) backspacecompare not test
+test.end
diff --git a/challenge-321/roger-bell-west/python/ch-1.py b/challenge-321/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..f7482985c5
--- /dev/null
+++ b/challenge-321/roger-bell-west/python/ch-1.py
@@ -0,0 +1,25 @@
+#! /usr/bin/python3
+
+def distinctaverage(a0):
+  a = a0.copy()
+  a.sort()
+  offset = len(a) - 1
+  res = set()
+  for i in range(int(len(a) / 2)):
+    res.add(a[i] + a[offset - i])
+  return len(res)
+
+import unittest
+
+class TestDistinctaverage(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(distinctaverage([1, 2, 4, 3, 5, 6]), 1, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(distinctaverage([0, 2, 4, 8, 3, 5]), 2, 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(distinctaverage([7, 3, 1, 0, 5, 9]), 2, 'example 3')
+
+unittest.main()
diff --git a/challenge-321/roger-bell-west/python/ch-2.py b/challenge-321/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..baf1c7a1c7
--- /dev/null
+++ b/challenge-321/roger-bell-west/python/ch-2.py
@@ -0,0 +1,28 @@
+#! /usr/bin/python3
+
+def backspacecompare(a, b):
+  sa = []
+  for i in [a, b]:
+    oa = []
+    for c in i:
+      if c == "#":
+        oa.pop()
+      else:
+        oa.append(c)
+    sa.append("".join(oa))
+  return sa[0] == sa[1]
+
+import unittest
+
+class TestBackspacecompare(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(backspacecompare("ab#c", "ad#c"), True, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(backspacecompare("ab##", "a#b#"), True, 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(backspacecompare("a#b", "c"), False, 'example 3')
+
+unittest.main()
diff --git a/challenge-321/roger-bell-west/raku/ch-1.p6 b/challenge-321/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..dca5b24b7f
--- /dev/null
+++ b/challenge-321/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,19 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 3;
+
+is(distinctaverage([1, 2, 4, 3, 5, 6]), 1, 'example 1');
+is(distinctaverage([0, 2, 4, 8, 3, 5]), 2, 'example 2');
+is(distinctaverage([7, 3, 1, 0, 5, 9]), 2, 'example 3');
+
+sub distinctaverage(@a0) {
+    my @a = @a0.sort({ $^a <=> $^b });
+    my $offset = @a.elems - 1;
+    my %res = SetHash.new;
+    for 0 ..^ floor(@a.elems / 2) -> $i {
+        %res{@a[$i] + @a[$offset - $i]}++;
+    }
+    %res.elems;
+}
diff --git a/challenge-321/roger-bell-west/raku/ch-2.p6 b/challenge-321/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..5b68c96366
--- /dev/null
+++ b/challenge-321/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,25 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 3;
+
+is(backspacecompare('ab#c', 'ad#c'), True, 'example 1');
+is(backspacecompare('ab##', 'a#b#'), True, 'example 2');
+is(backspacecompare('a#b', 'c'), False, 'example 3');
+
+sub backspacecompare($a, $b) {
+    my @sa;
+    for [$a, $b] -> $i {
+        my @oa;
+        for $i.comb -> $c {
+            if $c eq '#' {
+                @oa.pop;
+            } else {
+                @oa.push($c);
+            }
+        }
+        @sa.push(@oa.join(''));
+    }
+    @sa[0] eq @sa[1];
+}
diff --git a/challenge-321/roger-bell-west/ruby/ch-1.rb b/challenge-321/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..aa5eb3e0cd
--- /dev/null
+++ b/challenge-321/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,31 @@
+#! /usr/bin/ruby
+
+require 'set'
+
+def distinctaverage(a0)
+  a = a0.sort
+  offset = a.size - 1
+  res = Set.new
+  0.upto(a.size / 2 - 1) do |i|
+    res.add(a[i] + a[offset - i])
+  end
+  res.size
+end
+
+require 'test/unit'
+
+class TestDistinctaverage < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(1, distinctaverage([1, 2, 4, 3, 5, 6]))
+  end
+
+  def test_ex2
+    assert_equal(2, distinctaverage([0, 2, 4, 8, 3, 5]))
+  end
+
+  def test_ex3
+    assert_equal(2, distinctaverage([7, 3, 1, 0, 5, 9]))
+  end
+
+end
diff --git a/challenge-321/roger-bell-west/ruby/ch-2.rb b/challenge-321/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..9df57e641c
--- /dev/null
+++ b/challenge-321/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,35 @@
+#! /usr/bin/ruby
+
+def backspacecompare(a, b)
+  sa = Array.new
+  [a, b].each do |i|
+    oa = Array.new
+    i.chars.each do |c|
+      if c == '#'
+        oa.pop
+      else
+        oa.push(c)
+      end
+    end
+    sa.push(oa.join(""))
+  end
+  sa[0] == sa[1]
+end
+
+require 'test/unit'
+
+class TestBackspacecompare < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(true, backspacecompare('ab#c', 'ad#c'))
+  end
+
+  def test_ex2
+    assert_equal(true, backspacecompare('ab##', 'a#b#'))
+  end
+
+  def test_ex3
+    assert_equal(false, backspacecompare('a#b', 'c'))
+  end
+
+end
diff --git a/challenge-321/roger-bell-west/rust/ch-1.rs b/challenge-321/roger-bell-west/rust/ch-1.rs
new file mode 100755
index 0000000000..829a240e6d
--- /dev/null
+++ b/challenge-321/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,30 @@
+#! /bin/sh
+//usr/bin/env rustc --test $0 -o ${0}x && ./${0}x --nocapture; rm -f ${0}x ; exit
+
+use std::collections::HashSet;
+
+#[test]
+fn test_ex1() {
+    assert_eq!(distinctaverage(vec![1, 2, 4, 3, 5, 6]), 1);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(distinctaverage(vec![0, 2, 4, 8, 3, 5]), 2);
+}
+
+#[test]
+fn test_ex3() {
+    assert_eq!(distinctaverage(vec![7, 3, 1, 0, 5, 9]), 2);
+}
+
+fn distinctaverage(a0: Vec<u32>) -> usize {
+    let mut a = a0.clone();
+    a.sort();
+    let offset = a.len() - 1;
+    let mut res = HashSet::new();
+    for i in 0 .. a.len() / 2 {
+        res.insert(a[i] + a[offset - i]);
+    }
+    res.len()
+}
diff --git a/challenge-321/roger-bell-west/rust/ch-2.rs b/challenge-321/roger-bell-west/rust/ch-2.rs
new file mode 100755
index 0000000000..3111355721
--- /dev/null
+++ b/challenge-321/roger-bell-west/rust/ch-2.rs
@@ -0,0 +1,33 @@
+#! /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!(backspacecompare("ab#c", "ad#c"), true);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(backspacecompare("ab##", "a#b#"), true);
+}
+
+#[test]
+fn test_ex3() {
+    assert_eq!(backspacecompare("a#b", "c"), false);
+}
+
+fn backspacecompare(a: &str, b: &str) -> bool {
+    let mut sa: Vec<String> = Vec::new();
+    for i in [a, b] {
+        let mut oa = Vec::new();
+        for c in i.chars() {
+            if c == '#' {
+                oa.pop();
+            } else {
+                oa.push(c)
+            }
+        }
+        sa.push(oa.iter().collect());
+    }
+    sa[0] == sa[1]
+}
diff --git a/challenge-321/roger-bell-west/scala/ch-1.scala b/challenge-321/roger-bell-west/scala/ch-1.scala
new file mode 100644
index 0000000000..765aa14dc1
--- /dev/null
+++ b/challenge-321/roger-bell-west/scala/ch-1.scala
@@ -0,0 +1,35 @@
+import scala.collection.mutable
+
+object Distinctaverage {
+  def distinctaverage(a0: List[Int]): Int = {
+    val a = a0.sortWith(_ < _)
+    val offset = a.size - 1
+    val limit = a.size / 2
+    var res = mutable.Set.empty[Int]
+    for (i <- 0 to limit - 1) {
+      res += (a(i) + a(offset - i))
+    }
+    res.size
+  }
+  def main(args: Array[String]) {
+    if (distinctaverage(List(1, 2, 4, 3, 5, 6)) == 1) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    print(" ")
+    if (distinctaverage(List(0, 2, 4, 8, 3, 5)) == 2) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    print(" ")
+    if (distinctaverage(List(7, 3, 1, 0, 5, 9)) == 2) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    println("")
+
+  }
+}
diff --git a/challenge-321/roger-bell-west/scala/ch-2.scala b/challenge-321/roger-bell-west/scala/ch-