Merge pull request #12620 from Firedrake/rogerbw-challenge-337

RogerBW solutions for challenge no. 337

25 files changed, 1406 insertions, 0 deletions

diff --git a/challenge-337/roger-bell-west/crystal/ch-1.cr b/challenge-337/roger-bell-west/crystal/ch-1.cr
new file mode 100755
index 0000000000..28347ee415
--- /dev/null
+++ b/challenge-337/roger-bell-west/crystal/ch-1.cr
@@ -0,0 +1,31 @@
+#! /usr/bin/crystal
+
+def smallerthancurrent(a)
+  b = a.sort()
+  m = Hash(Int32, Int32).new
+  b.each_with_index do |v, i|
+    if !m.has_key?(v)
+      m[v] = i
+    end
+  end
+  a.map{|x| m[x]}
+end
+
+require "spec"
+describe "smallerthancurrent" do
+  it "test_ex1" do
+    smallerthancurrent([6, 5, 4, 8]).should eq [2, 1, 0, 3]
+  end
+  it "test_ex2" do
+    smallerthancurrent([7, 7, 7, 7]).should eq [0, 0, 0, 0]
+  end
+  it "test_ex3" do
+    smallerthancurrent([5, 4, 3, 2, 1]).should eq [4, 3, 2, 1, 0]
+  end
+  it "test_ex4" do
+    smallerthancurrent([-1, 0, 3, -2, 1]).should eq [1, 2, 4, 0, 3]
+  end
+  it "test_ex5" do
+    smallerthancurrent([0, 1, 1, 2, 0]).should eq [0, 2, 2, 4, 0]
+  end
+end
diff --git a/challenge-337/roger-bell-west/crystal/ch-2.cr b/challenge-337/roger-bell-west/crystal/ch-2.cr
new file mode 100755
index 0000000000..92301cc1ab
--- /dev/null
+++ b/challenge-337/roger-bell-west/crystal/ch-2.cr
@@ -0,0 +1,39 @@
+#! /usr/bin/crystal
+
+def oddmatrix(rows, cols, points)
+  rm = Set(Int32).new
+  cm = Set(Int32).new
+  points.each do |p|
+    if rm.includes?(p[0])
+      rm.delete(p[0])
+    else
+      rm.add(p[0])
+    end
+    if cm.includes?(p[1])
+      cm.delete(p[1])
+    else
+      cm.add(p[1])
+    end
+  end
+  rm.size * (cols - cm.size) +
+        cm.size * (rows - rm.size)
+end
+
+require "spec"
+describe "oddmatrix" do
+  it "test_ex1" do
+    oddmatrix(2, 3, [[0, 1], [1, 1]]).should eq 6
+  end
+  it "test_ex2" do
+    oddmatrix(2, 2, [[1, 1], [0, 0]]).should eq 0
+  end
+  it "test_ex3" do
+    oddmatrix(3, 3, [[0, 0], [1, 2], [2, 1]]).should eq 0
+  end
+  it "test_ex4" do
+    oddmatrix(1, 5, [[0, 2], [0, 4]]).should eq 2
+  end
+  it "test_ex5" do
+    oddmatrix(4, 2, [[1, 0], [3, 1], [2, 0], [0, 1]]).should eq 8
+  end
+end
diff --git a/challenge-337/roger-bell-west/javascript/ch-1.js b/challenge-337/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..9c51c05c65
--- /dev/null
+++ b/challenge-337/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,73 @@
+#! /usr/bin/node
+
+"use strict"
+
+function smallerthancurrent(a) {
+    let b = [...a];
+    b.sort(function(a, b) {return a-b});
+    let m = new Map;
+    b.forEach((v, i) => {
+        if (!m.has(v)) {
+            m.set(v, i);
+        }
+    });
+    return a.map( x => m.get(x) );
+}
+
+// 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(smallerthancurrent([6, 5, 4, 8]), [2, 1, 0, 3])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(smallerthancurrent([7, 7, 7, 7]), [0, 0, 0, 0])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(smallerthancurrent([5, 4, 3, 2, 1]), [4, 3, 2, 1, 0])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(smallerthancurrent([-1, 0, 3, -2, 1]), [1, 2, 4, 0, 3])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(smallerthancurrent([0, 1, 1, 2, 0]), [0, 2, 2, 4, 0])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-337/roger-bell-west/javascript/ch-2.js b/challenge-337/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..d1f0677096
--- /dev/null
+++ b/challenge-337/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,52 @@
+#! /usr/bin/node
+
+"use strict"
+
+function oddmatrix(rows, cols, points) {
+    let rm = new Set;
+    let cm = new Set;
+    for (let p of points) {
+        if (rm.has(p[0])) {
+            rm.delete(p[0]);
+        } else {
+            rm.add(p[0]);
+        }
+        if (cm.has(p[1])) {
+            cm.delete(p[1]);
+        } else {
+            cm.add(p[1]);
+        }
+    }
+    return rm.size * (cols - cm.size) + cm.size * (rows - rm.size);
+}
+
+if (oddmatrix(2, 3, [[0, 1], [1, 1]]) == 6) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (oddmatrix(2, 2, [[1, 1], [0, 0]]) == 0) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (oddmatrix(3, 3, [[0, 0], [1, 2], [2, 1]]) == 0) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (oddmatrix(1, 5, [[0, 2], [0, 4]]) == 2) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (oddmatrix(4, 2, [[1, 0], [3, 1], [2, 0], [0, 1]]) == 8) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-337/roger-bell-west/kotlin/ch-1.kt b/challenge-337/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..2341884f7e
--- /dev/null
+++ b/challenge-337/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,45 @@
+fun smallerthancurrent(a: List<Int>): List<Int> {
+    val b = a.sorted()
+    var m = mutableMapOf<Int, Int>()
+    for ((i, v) in b.withIndex()) {
+        if (!m.contains(v)) {
+            m.put(v, i)
+        }
+    }
+    return a.map{ m.getValue(it) }.toList()
+}
+
+fun main() {
+
+    if (smallerthancurrent(listOf(6, 5, 4, 8)) == listOf(2, 1, 0, 3)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (smallerthancurrent(listOf(7, 7, 7, 7)) == listOf(0, 0, 0, 0)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (smallerthancurrent(listOf(5, 4, 3, 2, 1)) == listOf(4, 3, 2, 1, 0)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (smallerthancurrent(listOf(-1, 0, 3, -2, 1)) == listOf(1, 2, 4, 0, 3)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (smallerthancurrent(listOf(0, 1, 1, 2, 0)) == listOf(0, 2, 2, 4, 0)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-337/roger-bell-west/kotlin/ch-2.kt b/challenge-337/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..76cc20a5f1
--- /dev/null
+++ b/challenge-337/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,52 @@
+fun oddmatrix(rows: Int, cols: Int, points: List<List<Int>>): Int {
+    var rm = mutableSetOf<Int>()
+    var cm = mutableSetOf<Int>()
+    for (p in points) {
+        if (rm.contains(p[0])) {
+            rm.remove(p[0])
+        } else {
+            rm.add(p[0])
+        }
+        if (cm.contains(p[1])) {
+            cm.remove(p[1])
+        } else {
+            cm.add(p[1])
+        }
+    }
+    return rm.size * (cols - cm.size) + cm.size * (rows - rm.size)
+}
+
+fun main() {
+
+    if (oddmatrix(2, 3, listOf(listOf(0, 1), listOf(1, 1))) == 6) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (oddmatrix(2, 2, listOf(listOf(1, 1), listOf(0, 0))) == 0) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (oddmatrix(3, 3, listOf(listOf(0, 0), listOf(1, 2), listOf(2, 1))) == 0) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (oddmatrix(1, 5, listOf(listOf(0, 2), listOf(0, 4))) == 2) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (oddmatrix(4, 2, listOf(listOf(1, 0), listOf(3, 1), listOf(2, 0), listOf(0, 1))) == 8) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-337/roger-bell-west/lua/ch-1.lua b/challenge-337/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..c0c8541010
--- /dev/null
+++ b/challenge-337/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,85 @@
+#! /usr/bin/lua
+
+function smallerthancurrent(a)
+   local b = {}
+   for _, x in ipairs(a) do
+      table.insert(b, x)
+   end
+   table.sort(b)
+   local m = {}
+   for i, v in ipairs(b) do
+      if m[v] == nil then
+         m[v] = i - 1
+      end
+   end
+   local out = {}
+   for _, x in ipairs(a) do
+      table.insert(out, m[x])
+   end
+   return out
+end
+
+-- 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
+
+if recursive_compare(smallerthancurrent({6, 5, 4, 8}), {2, 1, 0, 3}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(smallerthancurrent({7, 7, 7, 7}), {0, 0, 0, 0}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(smallerthancurrent({5, 4, 3, 2, 1}), {4, 3, 2, 1, 0}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(smallerthancurrent({-1, 0, 3, -2, 1}), {1, 2, 4, 0, 3}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(smallerthancurrent({0, 1, 1, 2, 0}), {0, 2, 2, 4, 0}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-337/roger-bell-west/lua/ch-2.lua b/challenge-337/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..946d52e7e8
--- /dev/null
+++ b/challenge-337/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,65 @@
+#! /usr/bin/lua
+
+function oddmatrix(rows, cols, points)
+   local rm = {}
+   local cm = {}
+   for _, p in ipairs(points) do
+      if rm[p[1]] == nil then
+         rm[p[1]] = true
+      else
+         rm[p[1]] = nil
+      end
+      if cm[p[2]] == nil then
+         cm[p[2]] = true
+      else
+         cm[p[2]] = nil
+      end
+   end
+   local cml = length(cm)
+   local rml = length(rm)
+   return rml * (cols - cml) + cml * (rows -rml)
+end
+
+function length(t)
+   local l = 0
+   for k, v in pairs(t) do
+      l = l + 1
+   end
+   return l
+end
+
+if oddmatrix(2, 3, {{0, 1}, {1, 1}}) == 6 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if oddmatrix(2, 2, {{1, 1}, {0, 0}}) == 0 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if oddmatrix(3, 3, {{0, 0}, {1, 2}, {2, 1}}) == 0 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if oddmatrix(1, 5, {{0, 2}, {0, 4}}) == 2 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if oddmatrix(4, 2, {{1, 0}, {3, 1}, {2, 0}, {0, 1}}) == 8 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-337/roger-bell-west/perl/ch-1.pl b/challenge-337/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..4283c29a12
--- /dev/null
+++ b/challenge-337/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,24 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 5;
+
+is_deeply(smallerthancurrent([6, 5, 4, 8]), [2, 1, 0, 3], 'example 1');
+is_deeply(smallerthancurrent([7, 7, 7, 7]), [0, 0, 0, 0], 'example 2');
+is_deeply(smallerthancurrent([5, 4, 3, 2, 1]), [4, 3, 2, 1, 0], 'example 3');
+is_deeply(smallerthancurrent([-1, 0, 3, -2, 1]), [1, 2, 4, 0, 3], 'example 4');
+is_deeply(smallerthancurrent([0, 1, 1, 2, 0]), [0, 2, 2, 4, 0], 'example 5');
+
+sub smallerthancurrent($a) {
+  my @b = sort {$::a <=> $::b} @{$a};
+  my %m;
+  while (my ($i, $v) = each @b) {
+    unless (exists $m{$v}) {
+      $m{$v} = $i;
+    }
+  }
+  return [map {$m{$_}} @{$a}];
+}
diff --git a/challenge-337/roger-bell-west/perl/ch-2.pl b/challenge-337/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..b9642dd43d
--- /dev/null
+++ b/challenge-337/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,32 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 5;
+
+is(oddmatrix(2, 3, [[0, 1], [1, 1]]), 6, 'example 1');
+is(oddmatrix(2, 2, [[1, 1], [0, 0]]), 0, 'example 2');
+is(oddmatrix(3, 3, [[0, 0], [1, 2], [2, 1]]), 0, 'example 3');
+is(oddmatrix(1, 5, [[0, 2], [0, 4]]), 2, 'example 4');
+is(oddmatrix(4, 2, [[1, 0], [3, 1], [2, 0], [0, 1]]), 8, 'example 5');
+
+sub oddmatrix($rows, $cols, $points) {
+  my %rm;
+  my %cm;
+  foreach my $p (@{$points}) {
+    if (exists $rm{$p->[0]}) {
+      delete $rm{$p->[0]};
+    } else {
+      $rm{$p->[0]} = 1;
+    }
+    if (exists $cm{$p->[1]}) {
+      delete $cm{$p->[1]};
+    } else {
+      $cm{$p->[1]} = 1;
+    }
+  }
+  (scalar %rm) * ($cols - (scalar %cm)) +
+    (scalar %cm) * ($rows - (scalar %rm));
+}
diff --git a/challenge-337/roger-bell-west/postscript/ch-1.ps b/challenge-337/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..4d07f49f91
--- /dev/null
+++ b/challenge-337/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,267 @@
+%!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 {
+    { quicksort.cmp } quicksort.with_comparator
+} 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
+
+/enumerate.array {
+    1 dict begin
+    /a exch def
+    [
+      0 1 a length 1 sub {
+          [ exch dup a exch get ]
+      } for
+    ]
+    end
+} 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.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
+
+/map { % array proc -> array
+    2 dict begin
+    /p exch def
+    [ exch
+      {
+          p
+      } forall
+    ]
+    end
+} 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
+
+/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
+
+/deepcopy {
+    2 dict begin
+    /a exch def
+    a type /dicttype eq {
+        <<
+            a keys {
+                /k exch def
+                k
+                a k get deepcopy
+            } forall
+        >>
+    } {
+        a type /arraytype eq {
+            [
+                a {
+                    deepcopy
+                } forall
+            ]
+        } {
+            a type /stringtype eq {
+                a dup length string cvs
+            } {
+                a
+            } ifelse
+        } ifelse
+    } 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
+
+/smallerthancurrent {
+    0 dict begin
+    /a exch def
+    /b a deepcopy quicksort def
+    /m 0 dict def
+    b enumerate.array {
+        aload pop
+        /v exch def
+        /i exch def
+        m v known not {
+            m v i put
+        } if
+    } forall
+    a { m exch get } map
+    end
+} bind def
+
+(smallerthancurrent) test.start
+[6 5 4 8] smallerthancurrent [2 1 0 3] deepeq test
+[7 7 7 7] smallerthancurrent [0 0 0 0] deepeq test
+[5 4 3 2 1] smallerthancurrent [4 3 2 1 0] deepeq test
+[-1 0 3 -2 1] smallerthancurrent [1 2 4 0 3] deepeq test
+[0 1 1 2 0] smallerthancurrent [0 2 2 4 0] deepeq test
+test.end
diff --git a/challenge-337/roger-bell-west/postscript/ch-2.ps b/challenge-337/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..05832d6c6f
--- /dev/null
+++ b/challenge-337/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,73 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/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 {
+    /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
+
+/oddmatrix {
+    0 dict begin
+    /points exch def
+    /cols exch def
+    /rows exch def
+    /rm 0 dict def
+    /cm 0 dict def
+    points {
+        aload pop
+        /p1 exch def
+        /p0 exch def
+        rm p0 known {
+            rm p0 undef
+        } {
+            rm p0 true put
+        } ifelse
+        cm p1 known {
+            cm p1 undef
+        } {
+            cm p1 true put
+        } ifelse
+    } forall
+    rm length cols cm length sub mul
+    cm length rows rm length sub mul
+    add
+    end
+} bind def
+
+(oddmatrix) test.start
+2 3 [[0 1] [1 1]] oddmatrix 6 eq test
+2 2 [[1 1] [0 0]] oddmatrix 0 eq test
+3 3 [[0 0] [1 2] [2 1]] oddmatrix 0 eq test
+1 5 [[0 2] [0 4]] oddmatrix 2 eq test
+4 2 [[1 0] [3 1] [2 0] [0 1]] oddmatrix 8 eq test
+test.end
diff --git a/challenge-337/roger-bell-west/python/ch-1.py b/challenge-337/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..7c7ba2fd5c
--- /dev/null
+++ b/challenge-337/roger-bell-west/python/ch-1.py
@@ -0,0 +1,31 @@
+#! /usr/bin/python3
+
+def smallerthancurrent(a):
+  b = a.copy()
+  b.sort()
+  m = dict()
+  for i, v in enumerate(b):
+    if v not in m:
+      m[v] = i
+  return [m[x] for x in a]
+
+import unittest
+
+class TestSmallerthancurrent(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(smallerthancurrent([6, 5, 4, 8]), [2, 1, 0, 3], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(smallerthancurrent([7, 7, 7, 7]), [0, 0, 0, 0], 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(smallerthancurrent([5, 4, 3, 2, 1]), [4, 3, 2, 1, 0], 'example 3')
+
+  def test_ex4(self):
+    self.assertEqual(smallerthancurrent([-1, 0, 3, -2, 1]), [1, 2, 4, 0, 3], 'example 4')
+
+  def test_ex5(self):
+    self.assertEqual(smallerthancurrent([0, 1, 1, 2, 0]), [0, 2, 2, 4, 0], 'example 5')
+
+unittest.main()
diff --git a/challenge-337/roger-bell-west/python/ch-2.py b/challenge-337/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..1137f8491b
--- /dev/null
+++ b/challenge-337/roger-bell-west/python/ch-2.py
@@ -0,0 +1,36 @@
+#! /usr/bin/python3
+
+def oddmatrix(rows, cols, points):
+  rm = set()
+  cm = set()
+  for p in points:
+    if p[0] in rm:
+      rm.discard(p[0])
+    else:
+      rm.add(p[0])
+    if p[1] in cm:
+      cm.discard(p[1])
+    else:
+      cm.add(p[1])
+  return len(rm) * (cols - len(cm)) + len(cm) * (rows - len(rm))
+
+import unittest
+
+class TestOddmatrix(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(oddmatrix(2, 3, [[0, 1], [1, 1]]), 6, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(oddmatrix(2, 2, [[1, 1], [0, 0]]), 0, 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(oddmatrix(3, 3, [[0, 0], [1, 2], [2, 1]]), 0, 'example 3')
+
+  def test_ex4(self):
+    self.assertEqual(oddmatrix(1, 5, [[0, 2], [0, 4]]), 2, 'example 4')
+
+  def test_ex5(self):
+    self.assertEqual(oddmatrix(4, 2, [[