Merge pull request #9024 from Firedrake/rogerbw-challenge-242

RogerBW solutions for challenge no. 242

21 files changed, 981 insertions, 0 deletions

diff --git a/challenge-242/roger-bell-west/javascript/ch-1.js b/challenge-242/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..7a4375078c
--- /dev/null
+++ b/challenge-242/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,65 @@
+#! /usr/bin/node
+
+"use strict"
+
+function unique(a) {
+    let ss = new Set;
+    let b = [];
+    for (let i of a) {
+        if (!ss.has(i)) {
+            b.push(i);
+            ss.add(i);
+        }
+    }
+    return b;
+}
+
+function halfmissing(a, bh) {
+    return unique(a.filter(n => !bh.has(n)))
+}
+
+function missingmembers(a, b) {
+    const ah = new Set(a);
+    const bh = new Set(b);
+    return [halfmissing(a, bh), halfmissing(b, ah)];
+}
+
+// by Frank Tan
+// https://stackoverflow.com/questions/38400594/javascript-deep-comparison
+function deepEqual(a,b)
+{
+    if( (typeof a == 'object' && a != null) &&
+        (typeof b == 'object' && b != null) )
+    {
+        var count = [0,0];
+        for( var key in a) count[0]++;
+        for( var key in b) count[1]++;
+        if( count[0]-count[1] != 0) {return false;}
+        for( var key in a)
+        {
+            if(!(key in b) || !deepEqual(a[key],b[key])) {return false;}
+        }
+        for( var key in b)
+        {
+            if(!(key in a) || !deepEqual(b[key],a[key])) {return false;}
+        }
+        return true;
+    }
+    else
+    {
+        return a === b;
+    }
+}
+
+if (deepEqual(missingmembers([1, 2, 3], [2, 4, 6]), [[1, 3], [4, 6]])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(missingmembers([1, 2, 3, 3], [1, 1, 2, 2]), [[3], []])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-242/roger-bell-west/javascript/ch-2.js b/challenge-242/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..f882ea2f06
--- /dev/null
+++ b/challenge-242/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,53 @@
+#! /usr/bin/node
+
+"use strict"
+
+// by Frank Tan
+// https://stackoverflow.com/questions/38400594/javascript-deep-comparison
+function deepEqual(a,b)
+{
+    if( (typeof a == 'object' && a != null) &&
+        (typeof b == 'object' && b != null) )
+    {
+        var count = [0,0];
+        for( var key in a) count[0]++;
+        for( var key in b) count[1]++;
+        if( count[0]-count[1] != 0) {return false;}
+        for( var key in a)
+        {
+            if(!(key in b) || !deepEqual(a[key],b[key])) {return false;}
+        }
+        for( var key in b)
+        {
+            if(!(key in a) || !deepEqual(b[key],a[key])) {return false;}
+        }
+        return true;
+    }
+    else
+    {
+        return a === b;
+    }
+}
+
+function flipmatrix(a) {
+    let b = [];
+    for (let row of a) {
+        let r2 = row.map(i => 1 - i);
+        r2.reverse();
+        b.push(r2);
+    }
+    return b;
+}
+
+if (deepEqual(flipmatrix([[1, 1, 0], [1, 0, 1], [0, 0, 0]]), [[1, 0, 0], [0, 1, 0], [1, 1, 1]])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(flipmatrix([[1, 1, 0, 0], [1, 0, 0, 1], [0, 1, 1, 1], [1, 0, 1, 0]]), [[1, 1, 0, 0], [0, 1, 1, 0], [0, 0, 0, 1], [1, 0, 1, 0]])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-242/roger-bell-west/kotlin/ch-1.kt b/challenge-242/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..e4f2edf224
--- /dev/null
+++ b/challenge-242/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,26 @@
+fun halfmissing(a: List<Int>, bh: Set<Int>): List<Int> {
+    return a.filter {n -> !bh.contains(n)}.distinct().toList()
+}
+
+fun missingmembers(a: List<Int>, b: List<Int>): List<List<Int>> {
+    val ah = a.toSet()
+    val bh = b.toSet()
+    return listOf(halfmissing(a, bh), halfmissing(b, ah))
+}
+
+fun main() {
+
+    if (missingmembers(listOf(1, 2, 3), listOf(2, 4, 6)) == listOf(listOf(1, 3), listOf(4, 6))) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (missingmembers(listOf(1, 2, 3, 3), listOf(1, 1, 2, 2)) == listOf(listOf(3), emptyList<Int>())) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-242/roger-bell-west/kotlin/ch-2.kt b/challenge-242/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..49c946cef0
--- /dev/null
+++ b/challenge-242/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,20 @@
+fun flipmatrix(a: List<List<Int>>): List<List<Int>> {
+    return a.map{row -> row.map{1 - it}.reversed()}
+}
+
+fun main() {
+
+    if (flipmatrix(listOf(listOf(1, 1, 0), listOf(1, 0, 1), listOf(0, 0, 0))) == listOf(listOf(1, 0, 0), listOf(0, 1, 0), listOf(1, 1, 1))) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (flipmatrix(listOf(listOf(1, 1, 0, 0), listOf(1, 0, 0, 1), listOf(0, 1, 1, 1), listOf(1, 0, 1, 0))) == listOf(listOf(1, 1, 0, 0), listOf(0, 1, 1, 0), listOf(0, 0, 0, 1), listOf(1, 0, 1, 0))) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-242/roger-bell-west/lua/ch-1.lua b/challenge-242/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..e720e01534
--- /dev/null
+++ b/challenge-242/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,85 @@
+#! /usr/bin/lua
+
+-- by Michael Anderson at
+-- https://stackoverflow.com/questions/8722620/comparing-two-index-tables-by-index-value-in-lua
+-- modified by Roger
+function recursive_compare(t1,t2)
+  -- Use usual comparison first.
+  if t1==t2 then return true end
+  -- We only support non-default behavior for tables
+  if (type(t1)~="table") then return false end
+  -- They better have the same metatables
+  local mt1 = getmetatable(t1)
+  local mt2 = getmetatable(t2)
+  if( not recursive_compare(mt1,mt2) ) then return false end
+  -- Build list of all keys
+  local kk = {}
+  for k1, _ in pairs(t1) do
+     kk[k1] = true
+  end
+  for k2, _ in pairs(t2) do
+     kk[k2] = true
+  end
+  -- Check each key that exists in at least one table
+  for _, k in ipairs(kk) do
+     if (not recursive_compare(t1[k], t2[k])) then
+        return false
+     end
+  end
+  return true
+end
+
+function unique(a)
+   local ss = {}
+   local b = {}
+   for _, i in ipairs(a) do
+      if ss[i] == nil then
+         table.insert(b, i)
+         ss[i] = true
+      end
+   end
+   return b
+end
+
+function halfmissing(a, bh)
+   local c = {}
+   for _, i in ipairs(a) do
+      if bh[i] == nil then
+         table.insert(c, i)
+      end
+   end
+   return unique(c)
+end
+
+function toset(a)
+   local ss = {}
+   for _, i in ipairs(a) do
+      ss[i] = true
+   end
+   return ss
+end
+
+
+function missingmembers(a, b)
+   local ah = toset(a)
+   local bh = toset(b)
+   return {
+      halfmissing(a, bh),
+      halfmissing(b, ah)
+   }
+end
+
+if recursive_compare(missingmembers({1, 2, 3}, {2, 4, 6}), {{1, 3}, {4, 6}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(missingmembers({1, 2, 3, 3}, {1, 1, 2, 2}), {{3}, {}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-242/roger-bell-west/lua/ch-2.lua b/challenge-242/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..a384c82dd9
--- /dev/null
+++ b/challenge-242/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,57 @@
+#! /usr/bin/lua
+
+-- by Michael Anderson at
+-- https://stackoverflow.com/questions/8722620/comparing-two-index-tables-by-index-value-in-lua
+-- modified by Roger
+function recursive_compare(t1,t2)
+  -- Use usual comparison first.
+  if t1==t2 then return true end
+  -- We only support non-default behavior for tables
+  if (type(t1)~="table") then return false end
+  -- They better have the same metatables
+  local mt1 = getmetatable(t1)
+  local mt2 = getmetatable(t2)
+  if( not recursive_compare(mt1,mt2) ) then return false end
+  -- Build list of all keys
+  local kk = {}
+  for k1, _ in pairs(t1) do
+     kk[k1] = true
+  end
+  for k2, _ in pairs(t2) do
+     kk[k2] = true
+  end
+  -- Check each key that exists in at least one table
+  for _, k in ipairs(kk) do
+     if (not recursive_compare(t1[k], t2[k])) then
+        return false
+     end
+  end
+  return true
+end
+
+function flipmatrix(a)
+   local b = {}
+   for _, row in ipairs(a) do
+      local r2 = {}
+      for _b, v in ipairs(row) do
+         table.insert(r2, 1, 1 - v)
+      end
+      table.insert(b, r2)
+   end
+   return b
+end
+
+if recursive_compare(flipmatrix({{1, 1, 0}, {1, 0, 1}, {0, 0, 0}}), {{1, 0, 0}, {0, 1, 0}, {1, 1, 1}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(flipmatrix({{1, 1, 0, 0}, {1, 0, 0, 1}, {0, 1, 1, 1}, {1, 0, 1, 0}}), {{1, 1, 0, 0}, {0, 1, 1, 0}, {0, 0, 0, 1}, {1, 0, 1, 0}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-242/roger-bell-west/perl/ch-1.pl b/challenge-242/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..7216e1687c
--- /dev/null
+++ b/challenge-242/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,25 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 2;
+
+is_deeply(missingmembers([1, 2, 3], [2, 4, 6]), [[1, 3], [4, 6]], 'example 1');
+is_deeply(missingmembers([1, 2, 3, 3], [1, 1, 2, 2]), [[3], []], 'example 2');
+
+use List::Util qw(uniq);
+
+sub halfmissing($a, $bh) {
+  return [uniq grep {!exists $bh->{$_}} @{$a}];
+}
+
+sub missingmembers($a, $b) {
+  my $ah = {map {$_ => 1} @{$a}};
+  my $bh = {map {$_ => 1} @{$b}};
+  return [
+    halfmissing($a, $bh),
+    halfmissing($b, $ah),
+      ];
+}
diff --git a/challenge-242/roger-bell-west/perl/ch-2.pl b/challenge-242/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..89da4f6938
--- /dev/null
+++ b/challenge-242/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,14 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 2;
+
+is_deeply(flipmatrix([[1, 1, 0], [1, 0, 1], [0, 0, 0]]), [[1, 0, 0], [0, 1, 0], [1, 1, 1]], 'example 1');
+is_deeply(flipmatrix([[1, 1, 0, 0], [1, 0, 0, 1], [0, 1, 1, 1], [1, 0, 1, 0]]), [[1, 1, 0, 0], [0, 1, 1, 0], [0, 0, 0, 1], [1, 0, 1, 0]], 'example 2');
+
+sub flipmatrix($a) {
+  return [map {[reverse map {1 - $_} @{$_}]} @{$a}];
+}
diff --git a/challenge-242/roger-bell-west/postscript/ch-1.ps b/challenge-242/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..8522cacd28
--- /dev/null
+++ b/challenge-242/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,171 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/filter { % array proc(bool) -> array
+    1 dict begin
+    /p exch def
+    [ exch
+      {
+          dup p not
+          {
+              pop
+          } if
+      } forall
+    ]
+    end
+} bind def
+
+/keys { % dict -> array of dict keys
+    [ exch
+      {
+          pop
+      } forall
+    ]
+} bind def
+
+/unique {
+    toset keys
+} 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
+
+/toset { % array -> dict of (value, true)
+    << exch
+       {
+           true
+       } forall
+    >>
+} 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
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+
+% end included library code
+
+/unique {
+    0 dict begin
+    /ss 0 dict def
+    [ exch
+      {
+          /i exch def
+          ss i known not {
+              i
+              ss i true put
+          } if
+      } forall
+    ]
+    end
+} bind def
+
+/halfmissing {
+    0 dict begin
+    /bh exch def
+    {
+        bh exch known not
+    } filter
+    unique
+    end
+} bind def
+
+/missingmembers {
+    0 dict begin
+    /b exch def
+    /a exch def
+    [
+        a b toset halfmissing
+        b a toset halfmissing
+    ]
+    end
+} bind def
+
+(missingmembers) test.start
+[1 2 3] [2 4 6] missingmembers [[1 3] [4 6]] deepeq test
+[1 2 3 3] [1 1 2 2] missingmembers [[3] []] deepeq test
+test.end
diff --git a/challenge-242/roger-bell-west/postscript/ch-2.ps b/challenge-242/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..6c70e8f06b
--- /dev/null
+++ b/challenge-242/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,132 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/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.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/reverse {
+    1 dict begin
+    dup length /l exch def
+    [ exch
+      aload pop
+      2 1 l {
+          -1 roll
+      } for
+    ]
+    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
+
+/map { % array proc -> array
+    2 dict begin
+    /p exch def
+    [ exch
+      {
+          p
+      } forall
+    ]
+    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
+
+
+% end included library code
+
+/flipmatrix {
+    {
+        {
+            1 exch sub
+        } map
+        reverse
+    } map
+} bind def
+
+(flipmatrix) test.start
+[[1 1 0] [1 0 1] [0 0 0]] flipmatrix [[1 0 0] [0 1 0] [1 1 1]] deepeq test
+[[1 1 0 0] [1 0 0 1] [0 1 1 1] [1 0 1 0]] flipmatrix [[1 1 0 0] [0 1 1 0] [0 0 0 1] [1 0 1 0]] deepeq test
+test.end
diff --git a/challenge-242/roger-bell-west/python/ch-1.py b/challenge-242/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..a4b970b293
--- /dev/null
+++ b/challenge-242/roger-bell-west/python/ch-1.py
@@ -0,0 +1,30 @@
+#! /usr/bin/python3
+
+def unique(a):
+  ss = set()
+  b = []
+  for i in a:
+    if i not in ss:
+      b.append(i)
+      ss.add(i)
+  return b
+
+def halfmissing(a, bh):
+  return unique(i for i in a if i not in bh)
+
+def missingmembers(a, b):
+  ah = set(a)
+  bh = set(b)
+  return [halfmissing(a, bh), halfmissing(b, ah)]
+
+import unittest
+
+class TestMissingmembers(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(missingmembers([1, 2, 3], [2, 4, 6]), [[1, 3], [4, 6]], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(missingmembers([1, 2, 3, 3], [1, 1, 2, 2]), [[3], []], 'example 2')
+
+unittest.main()
diff --git a/challenge-242/roger-bell-west/python/ch-2.py b/challenge-242/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..c01ccf6c74
--- /dev/null
+++ b/challenge-242/roger-bell-west/python/ch-2.py
@@ -0,0 +1,19 @@
+#! /usr/bin/python3
+
+def flipmatrix(a):
+  b = []
+  for row in a:
+    b.append(list(reversed([1 - i for i in row])))
+  return b
+
+import unittest
+
+class TestFlipmatrix(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(flipmatrix([[1, 1, 0], [1, 0, 1], [0, 0, 0]]), [[1, 0, 0], [0, 1, 0], [1, 1, 1]], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(flipmatrix([[1, 1, 0, 0], [1, 0, 0, 1], [0, 1, 1, 1], [1, 0, 1, 0]]), [[1, 1, 0, 0], [0, 1, 1, 0], [0, 0, 0, 1], [1, 0, 1, 0]], 'example 2')
+
+unittest.main()
diff --git a/challenge-242/roger-bell-west/raku/ch-1.p6 b/challenge-242/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..4b4bf48abc
--- /dev/null
+++ b/challenge-242/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,21 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 2;
+
+is-deeply(missingmembers([1, 2, 3], [2, 4, 6]), [[1, 3], [4, 6]], 'example 1');
+is-deeply(missingmembers([1, 2, 3, 3], [1, 1, 2, 2]), [[3], []], 'example 2');
+
+sub halfmissing(@a, $bh) {
+  return @a.grep({$bh{$_}:!exists}).unique.Array;
+}
+
+sub missingmembers(@a, @b) {
+  my $ah = @a.Set;
+  my $bh = @b.Set;
+  return [
+    halfmissing(@a, $bh),
+    halfmissing(@b, $ah),
+      ];
+}
diff --git a/challenge-242/roger-bell-west/raku/ch-2.p6 b/challenge-242/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..f2a19bae8b
--- /dev/null
+++ b/challenge-242/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,12 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 2;
+
+is-deeply(flipmatrix([[1, 1, 0], [1, 0, 1], [0, 0, 0]]), [[1, 0, 0], [0, 1, 0], [1, 1, 1]], 'example 1');
+is-deeply(flipmatrix([[1, 1, 0, 0], [1, 0, 0, 1], [0, 1, 1, 1], [1, 0, 1, 0]]), [[1, 1, 0, 0], [0, 1, 1, 0], [0, 0, 0, 1], [1, 0, 1, 0]], 'example 2');
+
+sub flipmatrix(@a) {
+  return @a.map({$_.map({1 - $_}).reverse.Array}).Array;
+}
diff --git a/challenge-242/roger-bell-west/ruby/ch-1.rb b/challenge-242/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..c34f2d7d75
--- /dev/null
+++ b/challenge-242/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,30 @@
+#! /usr/bin/ruby
+
+require 'set'
+
+def halfmissing(a, bh)
+  return a.find_all {|n| !bh.include?(n)}.uniq
+end
+
+def missingmembers(a, b)
+  ah = Set.new(a)
+  bh = Set.new(b)
+  return [
+    halfmissing(a, bh),
+    halfmissing(b, ah)
+  ]
+end
+
+require 'test/unit'
+
+class TestMissingmembers < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal([[1, 3], [4, 6]], missingmembers([1, 2, 3], [2, 4, 6]))
+  end
+
+  def test_ex2
+    assert_equal([[3], []], missingmembers([1, 2, 3, 3], [1, 1, 2, 2]))
+  end
+
+end
diff --git a/challenge-242/roger-bell-west/ruby/ch-2.rb b/challenge-242/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..47bf67b7ee
--- /dev/null
+++ b/challenge-242/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,19 @@
+#! /usr/bin/ruby
+
+def flipmatrix(a)
+  return a.collect{|r| r.collect{|m| 1-m}.reverse}
+end
+
+require 'test/unit'
+
+class TestFlipmatrix < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal([[1, 0, 0], [0, 1, 0], [1, 1, 1]], flipmatrix([[1, 1, 0], [1, 0, 1], [0, 0, 0]]))
+  end
+
+  def test_ex2
+    assert_equal([[1, 1, 0, 0], [0, 1, 1, 0], [0, 0, 0, 1], [1, 0, 1, 0]], flipmatrix([[1, 1, 0, 0], [1, 0, 0, 1], [0, 1, 1, 1], [1, 0, 1, 0]]))
+  end
+
+end
diff --git a/challenge-242/roger-bell-west/rust/ch-1.rs b/challenge-242/roger-bell-west/rust/ch-1.rs
new file mode 100755
index 0000000000..ecc248438b
--- /dev/null
+++ b/challenge-242/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,32 @@
+use itertools::Itertools;
+use std::collections::HashSet;
+
+#[test]
+fn test_ex1() {
+    assert_eq!(
+        missingmembers(vec![1, 2, 3], vec![2, 4, 6]),
+        vec![vec![1, 3], vec![4, 6]]
+    );
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(
+        missingmembers(vec![1, 2, 3, 3], vec![1, 1, 2, 2]),
+        vec![vec![3], Vec::<u32>::new()]
+    );
+}
+
+fn halfmissing(a: &Vec<u32>, bh: HashSet<&u32>) -> Vec<u32> {
+    a.iter()
+        .filter(|n| !bh.contains(n))
+        .unique()
+        .map(|i| *i)
+        .collect::<Vec<_>>()
+}
+
+fn missingmembers(a: Vec<u32>, b: Vec<u32>) -> Vec<Vec<u32>> {
+    let ah = a.iter().collect::<HashSet<_>>();
+    let bh = b.iter().collect::<HashSet<_>>();
+    vec![halfmissing(&a, bh), halfmissing(&b, ah)]
+}
diff --git a/challenge-242/roger-bell-west/rust/ch-2.rs b/challenge-242/roger-bell-west/rust/ch-2.rs
new file mode 100755
index 0000000000..65c9c55082
--- /dev/null
+++ b/challenge-242/roger-bell-west/rust/ch-2.rs
@@ -0,0 +1,38 @@
+#! /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!(
+        flipmatrix(vec![vec![1, 1, 0], vec![1, 0, 1], vec![0, 0, 0]]),
+        vec![vec![1, 0, 0], vec![0, 1, 0], vec![1, 1, 1]]
+    );
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(
+        flipmatrix(vec![
+            vec![1, 1, 0, 0],
+            vec![1, 0, 0, 1],
+            vec![0, 1, 1, 1],
+            vec![1, 0, 1, 0]
+        ]),
+        vec![
+            vec![1, 1, 0, 0],
+            vec![0, 1, 1, 0],
+            vec![0, 0, 0, 1],
+            vec![1, 0, 1, 0]
+        ]
+    );
+}
+
+fn flipmatrix(a: Vec<Vec<u8>>) -> Vec<Vec<u8>> {
+    let mut b = Vec::new();
+    for row in a {
+        let mut r2 = row.into_iter().map(|i| 1 - i).collect::<Vec<_>>();
+        r2.reverse();
+        b.push(r2);
+    }
+    b
+}
diff --git a/challenge-242/roger-bell-west/scala/ch-1.scala b/challenge-242/roger-bell-west/scala/ch-1.scala
new file mode 100644
index 0000000000..39fe097d39
--- /dev/null
+++ b/challenge-242/roger-bell-west/scala/ch-1.scala
@@ -0,0 +1,26 @@
+
+object Missingmembers {
+  def halfmissing(a: List[Int], bh: Set[Int]): List[Int] = {
+    return a.filter(n => !bh.contains(n)).distinct
+  }
+  def missingmembers(a: List[Int], b: List[Int]): List[List[Int]] = {
+    val ah = a.toSet
+    val bh = b.toSet
+    return List(halfmissing(a, bh), halfmissing(b, ah))
+  }
+  def main(args: Array[String]) {
+      if (missingmembers(List(1, 2, 3), List(2, 4, 6)) == List(List(1, 3), List(4, 6))) {
+          print("Pass")
+      } else {
+          print("Fail")
+      }
+      print(" ")
+      if (missingmembers(List(1, 2, 3, 3), List(1, 1, 2, 2)) == List(List(3), List())) {
+          print("Pass")
+      } else {
+          print("Fail")
+      }
+      println("")
+
+  }
+}
diff --git a/challenge-242/roger-bell-west/scala/ch-2.scala b/challenge-242/roger-bell-west/scala/ch-2.scala
new file mode 100644