Merge pull request #9161 from Firedrake/rogerbw-challenge-245

RogerBW solutions for challenge no. 245

21 files changed, 1071 insertions, 0 deletions

diff --git a/challenge-245/roger-bell-west/javascript/ch-1.js b/challenge-245/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..f3ea366d19
--- /dev/null
+++ b/challenge-245/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,51 @@
+#! /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 sortlanguage(langs, popularities) {
+    let ix = Array(langs.length).fill().map((element, index) => index);
+    ix.sort(function(a,b) {
+        return popularities[a] - popularities[b];
+    });
+    return ix.map(n => langs[n]);
+}
+
+if (deepEqual(sortlanguage(['perl', 'c', 'python'], [2, 1, 3]), ['c', 'perl', 'python'])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(sortlanguage(['c++', 'haskell', 'java'], [1, 3, 2]), ['c++', 'java', 'haskell'])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-245/roger-bell-west/javascript/ch-2.js b/challenge-245/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..e892748faa
--- /dev/null
+++ b/challenge-245/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,64 @@
+#! /usr/bin/node
+
+"use strict"
+
+function combinations(arr, k) {
+    let c = [];
+    for (let i = 0; i < k; i++) {
+        c.push(i);
+    }
+    c.push(arr.length);
+    c.push(0);
+    let out = [];
+    while (true) {
+        let inner = [];
+        for (let i = k-1; i >= 0; i--) {
+            inner.push(arr[c[i]]);
+        }
+        out.push(inner);
+        let j = 0;
+        while (c[j] + 1 == c[j + 1]) {
+            c[j] = j;
+            j += 1;
+        }
+        if (j >= k) {
+            break;
+        }
+        c[j] += 1;
+    }
+    return out;
+}
+
+function largestofthree(digits) {
+    let ordered = [...digits];
+    ordered.sort(function(a,b) {
+        return a-b;
+    });
+    let mx = 0;
+    for (let n = ordered.length - 1; n >= 0; n--) {
+        for (let c of combinations(ordered, n + 1)) {
+            let t = 0;
+            for (let d of c) {
+                t *= 10
+                t += d;
+            }
+            if (t > mx && t % 3 == 0) {
+                mx = t;
+            }
+        }
+    }
+    return mx;
+}
+
+if (largestofthree([8, 1, 9]) == 981) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (largestofthree([8, 6, 7, 1, 0]) == 8760) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-245/roger-bell-west/kotlin/ch-1.kt b/challenge-245/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..497fb6c708
--- /dev/null
+++ b/challenge-245/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,22 @@
+fun sortlanguage(langs: List<String>, popularities: List<Int>): List<String> {
+    var ix = ArrayList(generateSequence(0) { it + 1 }.take(langs.size).toList())
+    ix.sortBy { popularities[it] }
+    return ix.map {n -> langs[n]}
+}
+
+fun main() {
+
+    if (sortlanguage(listOf("perl", "c", "python"), listOf(2, 1, 3)) == listOf("c", "perl", "python")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (sortlanguage(listOf("c++", "haskell", "java"), listOf(1, 3, 2)) == listOf("c++", "java", "haskell")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-245/roger-bell-west/kotlin/ch-2.kt b/challenge-245/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..4f2e74575e
--- /dev/null
+++ b/challenge-245/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,61 @@
+fun combinations(arr: List<Int>, k: Int): List<List<Int>> {
+    var c = ArrayList<Int>()
+    for (i in 0 .. k-1) {
+        c.add(i)
+    }
+    c.add(arr.size)
+    c.add(0)
+    var out = ArrayList<List<Int>>()
+    while (true) {
+        var inner = ArrayList<Int>()
+        for (i in k-1 downTo 0) {
+            inner.add(arr[c[i]])
+        }
+        out.add(inner.toList())
+        var j = 0
+        while (c[j] + 1 == c[j + 1]) {
+            c[j] = j
+            j += 1
+        }
+        if (j >= k) {
+            break
+        }
+        c[j] += 1
+    }
+    return out.toList()
+}
+
+fun largestofthree(digits: List<Int>): Int {
+    val ordered = digits.sorted()
+    var mx = 0
+    for (n in ordered.size - 1 downTo 0) {
+        for (c in combinations(ordered, n + 1)) {
+            var t = 0
+            for (d in c) {
+                t *= 10
+                t += d
+            }
+            if (t > mx && t % 3 == 0) {
+                mx = t
+            }
+        }
+    }
+    return mx
+}
+
+fun main() {
+
+    if (largestofthree(listOf(8, 1, 9)) == 981) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (largestofthree(listOf(8, 6, 7, 1, 0)) == 8760) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-245/roger-bell-west/lua/ch-1.lua b/challenge-245/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..65b82c4f19
--- /dev/null
+++ b/challenge-245/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,58 @@
+#! /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 sortlanguage(langs, popularities)
+   local ix = {}
+   for n = 1, #langs do
+      table.insert(ix, n)
+   end
+   table.sort(ix, function (i, j) return popularities[i] < popularities[j] end)
+   local out = {}
+   for k, v in ipairs(ix) do
+      table.insert(out, langs[v])
+   end
+   return out
+end
+
+if recursive_compare(sortlanguage({"perl", "c", "python"}, {2, 1, 3}), {"c", "perl", "python"}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(sortlanguage({"c++", "haskell", "java"}, {1, 3, 2}), {"c++", "java", "haskell"}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-245/roger-bell-west/lua/ch-2.lua b/challenge-245/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..063ad63ad8
--- /dev/null
+++ b/challenge-245/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,61 @@
+#! /usr/bin/lua
+
+function combinations(arr, k)
+   local c = {}
+   for i = 1, k do
+      table.insert(c, i)
+   end
+   table.insert(c, #arr + 1)
+   table.insert(c, 0)
+   local out = {}
+   while true do
+      local inner = {}
+      for i = k, 1, -1 do
+         table.insert(inner, arr[c[i]])
+      end
+      table.insert(out, inner)
+      local j = 1
+      while c[j] + 1 == c[j + 1] do
+         c[j] = j
+         j = j + 1
+      end
+      if j > k then
+         break
+      end
+      c[j] = c[j] + 1
+   end
+   return ipairs(out)
+end
+
+function largestofthree(digits)
+   ordered = digits
+   table.sort(ordered, function (i,j) return i < j end)
+   local mx = 0
+   for n = #ordered, 1, -1 do
+      for _a, c in combinations(ordered, n) do
+         local t = 0
+         for _b, d in ipairs(c) do
+            t = t * 10 + d
+         end
+         if t > mx and t % 3 == 0 then
+            mx = t
+         end
+      end
+   end
+   return mx
+end
+
+if largestofthree({8, 1, 9}) == 981 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if largestofthree({8, 6, 7, 1, 0}) == 8760 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-245/roger-bell-west/perl/ch-1.pl b/challenge-245/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..8fed5fa309
--- /dev/null
+++ b/challenge-245/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,15 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 2;
+
+is_deeply(sortlanguage(['perl', 'c', 'python'], [2, 1, 3]), ['c', 'perl', 'python'], 'example 1');
+is_deeply(sortlanguage(['c++', 'haskell', 'java'], [1, 3, 2]), ['c++', 'java', 'haskell'], 'example 2');
+
+sub sortlanguage($langs, $popularities) {
+  my @ix = sort {$popularities->[$a] <=> $popularities->[$b]} (0 .. $#{$langs});
+  return [map {$langs->[$_]} @ix];
+}
diff --git a/challenge-245/roger-bell-west/perl/ch-2.pl b/challenge-245/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..04d6e280cc
--- /dev/null
+++ b/challenge-245/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,30 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 2;
+
+is(largestofthree([8, 1, 9]), 981, 'example 1');
+is(largestofthree([8, 6, 7, 1, 0]), 8760, 'example 2');
+
+use Algorithm::Combinatorics qw(combinations);
+
+sub largestofthree($digits) {
+  my @ordered = sort {$b <=> $a} @{$digits};
+  my $mx = 0;
+  foreach my $n (reverse(0 .. $#ordered)) {
+    foreach my $c (combinations(\@ordered, $n + 1)) {
+      my $t = 0;
+      foreach my $d (@{$c}) {
+        $t *= 10;
+        $t += $d;
+      }
+      if ($t > $mx && $t % 3 == 0) {
+        $mx = $t;
+      }
+    }
+  }
+  return $mx;
+}
diff --git a/challenge-245/roger-bell-west/postscript/ch-1.ps b/challenge-245/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..7ca0ca1362
--- /dev/null
+++ b/challenge-245/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,204 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/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.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
+
+/quicksort.with_keylist { % [ a c b ] [ keylist ] -> [ a b c ]
+    4 dict begin
+    /kg exch def
+    /arr exch def
+    /kl <<
+            0 1 arr length 1 sub {
+                /i exch def
+                arr i get
+                kg i get
+            } for
+        >> def
+    arr {
+        exch kl exch get exch kl exch get quicksort.cmp
+    } quicksort.with_comparator
+} 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
+
+/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
+
+/quicksort.cmp {
+    2 copy
+    lt {
+        pop pop -1
+    } {
+        gt {
+            1
+        } {
+            0
+        } ifelse
+    } ifelse
+} 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.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
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+
+% end included library code
+
+/sortlanguage {
+    quicksort.with_keylist
+} bind def
+
+(sortlanguage) test.start
+[(perl) (c) (python)] [2 1 3] sortlanguage [(c) (perl) (python)] deepeq test
+[(c++) (haskell) (java)] [1 3 2] sortlanguage [(c++) (java) (haskell)] deepeq test
+test.end
diff --git a/challenge-245/roger-bell-west/postscript/ch-2.ps b/challenge-245/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..870f26b893
--- /dev/null
+++ b/challenge-245/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,182 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/quicksort {
+    { quicksort.cmp } quicksort.with_comparator
+} bind def
+
+/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
+
+/combinations {
+    4 dict begin
+    /k exch def
+    /arr exch def
+    /c [
+        0 1 k 1 sub { } for
+        arr length
+        0
+    ] def
+    [
+        {
+            [
+                k 1 sub -1 0 {
+                    c exch get arr exch get
+                } for
+            ]
+            /j 0 def
+            {
+                c j get 1 add c j 1 add get ne {
+                    exit
+                } if
+                c j j put
+                /j j 1 add def
+            } loop
+            j k ge {
+                exit
+            } if
+            c j c j get 1 add put
+        } loop
+    ]
+    end
+} 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
+
+/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
+
+/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
+
+/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.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
+
+
+% end included library code
+
+/largestofthree {
+    0 dict begin
+    quicksort /ordered exch def
+    /mx 0 def
+    ordered length 1 sub 1 neg 0 {
+        ordered exch 1 add combinations {
+            /t 0 def
+            {
+                t 10 mul add /t exch def
+            } forall
+            t mx gt t 3 mod 0 eq and {
+                /mx t def
+            } if
+        } forall
+    } for
+    mx
+    end
+} bind def
+
+(largestofthree) test.start
+[8 1 9] largestofthree 981 eq test
+[8 6 7 1 0] largestofthree 8760 eq test
+test.end
diff --git a/challenge-245/roger-bell-west/python/ch-1.py b/challenge-245/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..f2714b0bc2
--- /dev/null
+++ b/challenge-245/roger-bell-west/python/ch-1.py
@@ -0,0 +1,18 @@
+#! /usr/bin/python3
+
+def sortlanguage(langs, popularities):
+  ix = list(range(len(langs)))
+  ix.sort(key = lambda n: popularities[n])
+  return [langs[n] for n in ix]
+
+import unittest
+
+class TestSortlanguage(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(sortlanguage(["perl", "c", "python"], [2, 1, 3]), ["c", "perl", "python"], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(sortlanguage(["c++", "haskell", "java"], [1, 3, 2]), ["c++", "java", "haskell"], 'example 2')
+
+unittest.main()
diff --git a/challenge-245/roger-bell-west/python/ch-2.py b/challenge-245/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..6460369c52
--- /dev/null
+++ b/challenge-245/roger-bell-west/python/ch-2.py
@@ -0,0 +1,30 @@
+#! /usr/bin/python3
+
+from itertools import combinations
+
+def largestofthree(digits):
+  ordered = digits.copy()
+  ordered.sort()
+  ordered.reverse()
+  mx = 0
+  for n in range(0, len(ordered)):
+    for c in combinations(ordered, n + 1):
+      t = 0
+      for d in c:
+        t *= 10
+        t += d
+      if t > mx and t % 3 == 0:
+        mx = t
+  return mx
+
+import unittest
+
+class TestLargestofthree(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(largestofthree([8, 1, 9]), 981, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(largestofthree([8, 6, 7, 1, 0]), 8760, 'example 2')
+
+unittest.main()
diff --git a/challenge-245/roger-bell-west/raku/ch-1.p6 b/challenge-245/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..6bb0e41b68
--- /dev/null
+++ b/challenge-245/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,13 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 2;
+
+is-deeply(sortlanguage(['perl', 'c', 'python'], [2, 1, 3]), ['c', 'perl', 'python'], 'example 1');
+is-deeply(sortlanguage(['c++', 'haskell', 'java'], [1, 3, 2]), ['c++', 'java', 'haskell'], 'example 2');
+
+sub sortlanguage(@langs, @popularities) {
+    my @ix = [0 .. @langs.end].sort({@popularities[$^a] <=> @popularities[$^b]});
+    return Array(@ix.map({@langs[$_]}));
+}
diff --git a/challenge-245/roger-bell-west/raku/ch-2.p6 b/challenge-245/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..d5f187c927
--- /dev/null
+++ b/challenge-245/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,26 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 2;
+
+is(largestofthree([8, 1, 9]), 981, 'example 1');
+is(largestofthree([8, 6, 7, 1, 0]), 8760, 'example 2');
+
+sub largestofthree(@digits) {
+    my @ordered = @digits.sort({$^b <=> $^a});
+    my $mx = 0;
+    for (0 .. @ordered.end).reverse -> $n {
+        for combinations(@ordered, $n + 1) -> @c {
+            my $t = 0;
+            for @c -> $d {
+                $t *= 10;
+                $t += $d;
+            }
+            if ($t > $mx && $t % 3 == 0) {
+                $mx = $t;
+            }
+        }
+    }
+    return $mx;
+}
diff --git a/challenge-245/roger-bell-west/ruby/ch-1.rb b/challenge-245/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..4ead71351e
--- /dev/null
+++ b/challenge-245/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,21 @@
+#! /usr/bin/ruby
+
+def sortlanguage(langs, popularities)
+  ix = (0...langs.length).to_a
+  ix = ix.sort_by {|n| popularities[n]}
+  return ix.collect {|n| langs[n]}
+end
+
+require 'test/unit'
+
+class TestSortlanguage < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(['c', 'perl', 'python'], sortlanguage(['perl', 'c', 'python'], [2, 1, 3]))
+  end
+
+  def test_ex2
+    assert_equal(['c++', 'java', 'haskell'], sortlanguage(['c++', 'haskell', 'java'], [1, 3, 2]))
+  end
+
+end
diff --git a/challenge-245/roger-bell-west/ruby/ch-2.rb b/challenge-245/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..b8ee053ea3
--- /dev/null
+++ b/challenge-245/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,33 @@
+#! /usr/bin/ruby
+
+def largestofthree(digits)
+  ordered = digits.sort {|a,b| b <=> a}
+  mx = 0
+  (ordered.length-1).downto(0) do |n|
+    ordered.combination(n + 1) do |c|
+      t = 0
+      c.each do |d|
+        t *= 10
+        t += d
+      end
+      if t > mx && t % 3 == 0 then
+        mx = t
+      end
+    end
+  end
+  return mx
+end
+
+require 'test/unit'
+
+class TestLargestofthree < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(981, largestofthree([8, 1, 9]))
+  end
+
+  def test_ex2
+    assert_equal(8760, largestofthree([8, 6, 7, 1, 0]))
+  end
+
+end
diff --git a/challenge-245/roger-bell-west/rust/ch-1.rs b/challenge-245/roger-bell-west/rust/ch-1.rs
new file mode 100755
index 0000000000..ef1fb3b415
--- /dev/null
+++ b/challenge-245/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,24 @@
+#! /bin/sh
+//usr/bin/env rustc --test $0 -o ${0}x && ./${0}x --nocapture; rm -f ${0}x ; exit
+
+fn sortlanguage(langs: Vec<&str>, popularities: Vec<u32>) -> Vec<String> {
+    let mut ix = (0..langs.len()).collect::<Vec<usize>>();
+    ix.sort_unstable_by_key(|n| popularities[*n]);
+    ix.iter().map(|n| langs[*n].to_string()).collect::<Vec<String>>()
+}
+
+#[test]
+fn test_ex1() {
+    assert_eq!(
+        sortlanguage(vec!["perl", "c", "python"], vec![2, 1, 3]),
+        vec!["c", "perl", "python"]
+    );
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(
+        sortlanguage(vec!["c++", "haskell", "java"], vec![1, 3, 2]),
+        vec!["c++", "java", "haskell"]
+    );
+}
diff --git a/challenge-245/roger-bell-west/rust/ch-2.rs b/challenge-245/roger-bell-west/rust/ch-2.rs
new file