From f8752958679af48261bd42f9c2457217bcec9e81 Mon Sep 17 00:00:00 2001
From: Roger Bell_West <roger@firedrake.org>
Date: Tue, 21 Jan 2025 11:03:01 +0000
Subject: RogerBW solutions for challenge no. 305

---
 challenge-305/roger-bell-west/crystal/ch-1.cr    |  66 +++++
 challenge-305/roger-bell-west/crystal/ch-2.cr    |  36 +++
 challenge-305/roger-bell-west/javascript/ch-1.js |  89 +++++++
 challenge-305/roger-bell-west/javascript/ch-2.js |  74 ++++++
 challenge-305/roger-bell-west/kotlin/ch-1.kt     |  76 ++++++
 challenge-305/roger-bell-west/kotlin/ch-2.kt     |  48 ++++
 challenge-305/roger-bell-west/lua/ch-1.lua       |  92 +++++++
 challenge-305/roger-bell-west/lua/ch-2.lua       |  86 ++++++
 challenge-305/roger-bell-west/perl/ch-1.pl       |  26 ++
 challenge-305/roger-bell-west/perl/ch-2.pl       |  35 +++
 challenge-305/roger-bell-west/postscript/ch-1.ps | 183 +++++++++++++
 challenge-305/roger-bell-west/postscript/ch-2.ps | 318 +++++++++++++++++++++++
 challenge-305/roger-bell-west/python/ch-1.py     |  57 ++++
 challenge-305/roger-bell-west/python/ch-2.py     |  30 +++
 challenge-305/roger-bell-west/raku/ch-1.p6       |  51 ++++
 challenge-305/roger-bell-west/raku/ch-2.p6       |  31 +++
 challenge-305/roger-bell-west/ruby/ch-1.rb       |  34 +++
 challenge-305/roger-bell-west/ruby/ch-2.rb       |  40 +++
 challenge-305/roger-bell-west/rust/ch-1.rs       |  70 +++++
 challenge-305/roger-bell-west/rust/ch-2.rs       |  37 +++
 challenge-305/roger-bell-west/scala/ch-1.scala   |  80 ++++++
 challenge-305/roger-bell-west/scala/ch-2.scala   |  41 +++
 challenge-305/roger-bell-west/tests.json         |  36 +++
 23 files changed, 1636 insertions(+)
 create mode 100755 challenge-305/roger-bell-west/crystal/ch-1.cr
 create mode 100755 challenge-305/roger-bell-west/crystal/ch-2.cr
 create mode 100755 challenge-305/roger-bell-west/javascript/ch-1.js
 create mode 100755 challenge-305/roger-bell-west/javascript/ch-2.js
 create mode 100644 challenge-305/roger-bell-west/kotlin/ch-1.kt
 create mode 100644 challenge-305/roger-bell-west/kotlin/ch-2.kt
 create mode 100755 challenge-305/roger-bell-west/lua/ch-1.lua
 create mode 100755 challenge-305/roger-bell-west/lua/ch-2.lua
 create mode 100755 challenge-305/roger-bell-west/perl/ch-1.pl
 create mode 100755 challenge-305/roger-bell-west/perl/ch-2.pl
 create mode 100644 challenge-305/roger-bell-west/postscript/ch-1.ps
 create mode 100644 challenge-305/roger-bell-west/postscript/ch-2.ps
 create mode 100755 challenge-305/roger-bell-west/python/ch-1.py
 create mode 100755 challenge-305/roger-bell-west/python/ch-2.py
 create mode 100755 challenge-305/roger-bell-west/raku/ch-1.p6
 create mode 100755 challenge-305/roger-bell-west/raku/ch-2.p6
 create mode 100755 challenge-305/roger-bell-west/ruby/ch-1.rb
 create mode 100755 challenge-305/roger-bell-west/ruby/ch-2.rb
 create mode 100755 challenge-305/roger-bell-west/rust/ch-1.rs
 create mode 100755 challenge-305/roger-bell-west/rust/ch-2.rs
 create mode 100644 challenge-305/roger-bell-west/scala/ch-1.scala
 create mode 100644 challenge-305/roger-bell-west/scala/ch-2.scala
 create mode 100644 challenge-305/roger-bell-west/tests.json

diff --git a/challenge-305/roger-bell-west/crystal/ch-1.cr b/challenge-305/roger-bell-west/crystal/ch-1.cr
new file mode 100755
index 0000000000..67645dd0e7
--- /dev/null
+++ b/challenge-305/roger-bell-west/crystal/ch-1.cr
@@ -0,0 +1,66 @@
+#! /usr/bin/crystal
+
+def isqrt(s)
+  if s <= 1
+    return s
+  end
+  x0 = s / 2;
+  x1 = (x0 + s / x0) / 2;
+  while x1 < x0
+    x0 = x1
+    x1 = (x0 + s / x0) / 2
+  end    
+  x0
+end
+
+def is_prime(n)
+  if n == 1
+    return false
+  end
+  if n>2 && n%2==0 
+    return false
+  end
+  if n>3 && n%3==0
+    return false
+  end
+  lim = isqrt(n)
+  k6 = 0;
+  while true
+    k6 += 6
+    (k6 - 1).step(to: k6 + 1, by: 2) do |t|
+      if t <= lim
+        if n % t == 0
+          return false
+        end
+      else
+        return true
+      end
+    end
+  end
+end
+
+def binaryprefix(a)
+  out = Array(Bool).new
+  n = 0
+  a.each do |x|
+    n *= 2
+    if x == 1
+      n += 1
+    end
+    out.push(is_prime(n))
+  end
+  out
+end
+
+require "spec"
+describe "binaryprefix" do
+  it "test_ex1" do
+    binaryprefix([1, 0, 1]).should eq [false, true, true]
+  end
+  it "test_ex2" do
+    binaryprefix([1, 1, 0]).should eq [false, true, false]
+  end
+  it "test_ex3" do
+    binaryprefix([1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]).should eq [false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true]
+  end
+end
diff --git a/challenge-305/roger-bell-west/crystal/ch-2.cr b/challenge-305/roger-bell-west/crystal/ch-2.cr
new file mode 100755
index 0000000000..768adccfc3
--- /dev/null
+++ b/challenge-305/roger-bell-west/crystal/ch-2.cr
@@ -0,0 +1,36 @@
+#! /usr/bin/crystal
+
+def aliendictionary(a, dc)
+  mxl = a.map { |x| x.size }.max
+  dh = Hash(Char, Int64).new
+  dc.each_with_index do |c, i|
+    dh[c] = i.to_i64
+  end
+  b = a
+  numerics = Hash(String, Int64).new
+  b.each do |w|
+    n = 0.to_i64
+    cc = w.chars
+    0.upto(mxl - 1) do |i|
+      n *= 27.to_i64
+      if i < w.size
+        n += dh[cc[i]]
+      end
+    end
+    numerics[w] = n
+  end
+  b.sort! do |i, j|
+    numerics[i] <=> numerics[j]
+  end
+  b
+end
+
+require "spec"
+describe "aliendictionary" do
+  it "test_ex1" do
+    aliendictionary(["perl", "python", "raku"], ['h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z']).should eq ["raku", "python", "perl"]
+  end
+  it "test_ex2" do
+    aliendictionary(["the", "weekly", "challenge"], ['c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z']).should eq ["challenge", "the", "weekly"]
+  end
+end
diff --git a/challenge-305/roger-bell-west/javascript/ch-1.js b/challenge-305/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..951d12bf8a
--- /dev/null
+++ b/challenge-305/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,89 @@
+#! /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 is_prime(candidate) {
+    if (candidate<2) {
+        return false
+    } else if (candidate==2) {
+        return true
+    } else if (candidate==3) {
+        return true
+    } else if (candidate % 2 == 0) {
+        return false
+    } else if (candidate % 3 == 0) {
+        return false
+    }
+    let anchor=0
+    let limit=Math.floor(Math.sqrt(candidate))
+    while (1) {
+        anchor+=6
+        for (let t = anchor-1; t <= anchor+1; t += 2) {
+            if (t > limit) {
+                return true
+            }
+            if (candidate % t == 0) {
+                return false
+            }
+        }
+    }
+}
+
+function binaryprefix(a) {
+    let out = [];
+    let n = 0;
+    for (let x of a) {
+        n *= 2
+        if (x == 1) {
+            n += 1;
+        }
+        out.push(is_prime(n));
+    }
+    return out;
+}
+
+if (deepEqual(binaryprefix([1, 0, 1]), [false, true, true])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(binaryprefix([1, 1, 0]), [false, true, false])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(binaryprefix([1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]), [false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-305/roger-bell-west/javascript/ch-2.js b/challenge-305/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..3b9bf69629
--- /dev/null
+++ b/challenge-305/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,74 @@
+#! /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 aliendictionary(a, dc) {
+    const mxl = Math.max(...a.map(x => x.length));
+    let dh = new Map;
+    dc.forEach((c, i) => {
+        dh.set(c, i + 1);
+    });
+    let b = [...a];
+    let numerics = new Map;
+    for (let w of a) {
+        let n = 0n;
+        let cc = w.split("");
+        for (let i = 0; i < mxl; i++) {
+            n *= 27n;
+            if (i < w.length) {
+                n += BigInt(dh.get(cc[i]));
+            }
+        }
+        numerics.set(w, n);
+    }
+    b.sort(function(i, j) {
+        const d = numerics.get(i) - numerics.get(j);
+        if (d < 0) {
+            return -1;
+        } else if (d > 0) {
+            return 1;
+        }
+        return 0;
+    });
+    return b;
+}
+
+if (deepEqual(aliendictionary(['perl', 'python', 'raku'], ['h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z']), ['raku', 'python', 'perl'])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (deepEqual(aliendictionary(['the', 'weekly', 'challenge'], ['c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z']), ['challenge', 'the', 'weekly'])) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-305/roger-bell-west/kotlin/ch-1.kt b/challenge-305/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..27e9070714
--- /dev/null
+++ b/challenge-305/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,76 @@
+fun isqrt(s: Int): Int {
+    if (s <= 1) {
+        return s
+    } else {
+        var x0 = s / 2
+        var x1 = (x0 + s / x0) / 2
+        while (x1 < x0) {
+            x0 = x1
+            x1 = (x0 + s / x0) / 2
+        }
+        return x0
+    }
+}
+
+fun is_prime(candidate: Int): Boolean {
+    if (candidate < 2) {
+        return false
+    } else if (candidate==2) {
+        return true
+    } else if (candidate==3) {
+        return true
+    } else if (candidate % 2 == 0) {
+        return false
+    } else if (candidate % 3 == 0) {
+        return false
+    }
+    var anchor=0
+    val limit = isqrt(candidate)
+    while (true) {
+        anchor += 6
+        for (t in anchor-1..anchor+1 step 2) {
+            if (t > limit) {
+                return true
+            }
+            if (candidate % t == 0) {
+                return false
+            }
+        }
+    }
+}
+
+fun binaryprefix(a: List<Int>): List<Boolean> {
+    var out =  ArrayList<Boolean>()
+    var n = 0
+    for (x in a) {
+        n *= 2
+        if (x == 1) {
+            n += 1
+        }
+        out.add(is_prime(n))
+    }
+    return out.toList()
+}
+
+fun main() {
+
+    if (binaryprefix(listOf(1, 0, 1)) == listOf(false, true, true)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (binaryprefix(listOf(1, 1, 0)) == listOf(false, true, false)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (binaryprefix(listOf(1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1)) == listOf(false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true)) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-305/roger-bell-west/kotlin/ch-2.kt b/challenge-305/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..d678e4d8e1
--- /dev/null
+++ b/challenge-305/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,48 @@
+fun aliendictionary(a: List<String>, dc: List<Char>): List<String> {
+    val mxl = a.map{it.length}.maxOrNull()!!
+    var dh = mutableMapOf<Char, Int>()
+    dc.forEachIndexed{i, c ->
+                          dh.set(c, i + 1)
+    }
+    var numerics = mutableMapOf<String, Long>()
+    for (w in a) {
+        var n = 0.toLong()
+        val cc = w.toList()
+        for (i in 0 .. mxl - 1) {
+            n *= 27.toLong()
+            if (i < w.length) {
+                n += dh.getValue(cc[i]).toLong()
+            }
+        }
+        numerics.set(w, n)
+    }
+    val customComparator = Comparator {
+        i: String, j: String ->
+            val d = numerics.getValue(i) - numerics.getValue(j)
+        if (d > 0L) {
+            1
+        } else if (d < 0L) {
+            -1
+        } else {
+            0
+        }
+    }
+    return a.sortedWith(customComparator)
+}
+
+fun main() {
+
+    if (aliendictionary(listOf("perl", "python", "raku"), listOf('h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z')) == listOf("raku", "python", "perl")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(' ')
+    if (aliendictionary(listOf("the", "weekly", "challenge"), listOf('c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z')) == listOf("challenge", "the", "weekly")) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-305/roger-bell-west/lua/ch-1.lua b/challenge-305/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..a5a16f3d93
--- /dev/null
+++ b/challenge-305/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,92 @@
+#! /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 is_prime(candidate)
+   if candidate<2 then
+      return false
+   elseif candidate==2 then
+      return true
+   elseif candidate==3 then
+      return true
+   elseif candidate % 2 == 0 then
+      return false
+   elseif candidate % 3 == 0 then
+      return false
+   end
+   local anchor=0
+   local limit=math.floor(math.sqrt(candidate))
+   while true do
+      anchor = anchor + 6
+      for t = anchor-1,anchor+1,2 do
+         if t > limit then
+            return true
+         end
+         if candidate % t == 0 then
+            return false
+         end
+      end
+   end
+end
+
+function binaryprefix(a)
+   local out = {}
+   local n = 0
+   for _, x in ipairs(a) do
+      n = n * 2
+      if x == 1 then
+         n = n + 1
+      end
+      table.insert(out, is_prime(n))
+   end
+   return out
+end
+
+if recursive_compare(binaryprefix({1, 0, 1}), {false, true, true}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(binaryprefix({1, 1, 0}), {false, true, false}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(binaryprefix({1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1}), {false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-305/roger-bell-west/lua/ch-2.lua b/challenge-305/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..e9974e511a
--- /dev/null
+++ b/challenge-305/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,86 @@
+#! /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 split(t)
+   local cl = {}
+   string.gsub(t,
+               "(.)",
+               function(c)
+                  table.insert(cl, c)
+               end
+   )
+   return cl
+end
+
+function aliendictionary(a, dc)
+   local mxl = 0
+   for _, w in ipairs(a) do
+      mxl = math.max(mxl, #w)
+   end
+   local dh = {}
+   for i, c in ipairs(dc) do
+      dh[c] = i
+   end
+   local b = a
+   local numerics = {}
+   for _, w in ipairs(a) do
+      local n = 0
+      local cc = split(w)
+      for i = 1, mxl do
+         n = n * 27
+         if i <= #w then
+            n = n + dh[cc[i]]
+         end
+      end
+      numerics[w] = n
+   end
+   table.sort(b,
+              function(i, j)
+                 return numerics[i] < numerics[j]
+              end
+   )
+   return b
+end
+
+if recursive_compare(aliendictionary({"perl", "python", "raku"}, {"h", "l", "a", "b", "y", "d", "e", "f", "g", "i", "r", "k", "m", "n", "o", "p", "q", "j", "s", "t", "u", "v", "w", "x", "c", "z"}), {"raku", "python", "perl"}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(aliendictionary({"the", "weekly", "challenge"}, {"c", "o", "r", "l", "d", "a", "b", "t", "e", "f", "g", "h", "i", "j", "k", "m", "n", "p", "q", "s", "w", "u", "v", "x", "y", "z"}), {"challenge", "the", "weekly"}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-305/roger-bell-west/perl/ch-1.pl b/challenge-305/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..e05413d206
--- /dev/null
+++ b/challenge-305/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,26 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 3;
+
+is_deeply(binaryprefix([1, 0, 1]), [0, 1, 1], 'example 1');
+is_deeply(binaryprefix([1, 1, 0]), [0, 1, 0], 'example 2');
+is_deeply(binaryprefix([1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]), [0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1], 'example 3');
+
+use Math::Prime::Util qw(is_prime);
+
+sub binaryprefix($a) {
+  my @out;
+  my $n = 0;
+  foreach my $x (@{$a}) {
+    $n *= 2;
+    if ($x == 1) {
+      $n++;
+    }
+    push @out, is_prime($n)?1:0;
+  }
+  \@out;
+}
diff --git a/challenge-305/roger-bell-west/perl/ch-2.pl b/challenge-305/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..ba5b1724b4
--- /dev/null
+++ b/challenge-305/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,35 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 2;
+
+is_deeply(aliendictionary(['perl', 'python', 'raku'], ['h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z']), ['raku', 'python', 'perl'], 'example 1');
+is_deeply(aliendictionary(['the', 'weekly', 'challenge'], ['c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z']), ['challenge', 'the', 'weekly'], 'example 2');
+
+use List::Util qw(max);
+
+sub aliendictionary($a, $dc) {
+  my $mxl = max(map {length($_)} @{$a});
+  my %dh;
+  while (my ($i, $c) = each @{$dc}) {
+    $dh{$c} = $i + 1;
+  }
+  my @b = @{$a};
+  my %numerics;
+  foreach my $w (@b) {
+    my $n = 0;
+    my @cc = split '', $w;
+    foreach my $i (0 .. $mxl - 1) {
+      $n *= 27;
+      if ($i < length($w)) {
+        $n += $dh{$cc[$i]};
+      }
+    }
+    $numerics{$w} = $n;
+  }
+  @b = sort { $numerics{$::a} <=> $numerics{$::b} } @b;
+  return \@b;
+}
diff --git a/challenge-305/roger-bell-west/postscript/ch-1.ps b/challenge-305/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..4515cf8337
--- /dev/null
+++ b/challenge-305/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,183 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/isqrt {
+    0 dict begin
+    /s exch def
+    s 1 le {
+        s
+    } {
+        /x0 s 2 idiv def
+        /x1 x0 s x0 idiv add 2 idiv def
+        {
+            x1 x0 ge {
+                exit
+            } if
+            /x0 x1 def
+            /x1 x0 s x0 idiv add 2 idiv def
+        } loop
+        x0
+    } ifelse
+    end
+} 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
+
+/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.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
+
+/isprime {
+    4 dict begin
+    /candidate exch def
+    1 {
+        candidate 2 lt {
+            false
+            exit
+        } if
+        candidate 2 eq {
+            true
+            exit
+        } if
+        candidate 2 mod 0 eq {
+            false
+            exit
+        } if
+        candidate 3 eq {
+            true
+            exit
+        } if
+        candidate 3 mod 0 eq {
+            false
+            exit
+        } if
+        /prime true def
+        /limit candidate isqrt 1 add def
+        /anchor 0 def
+        {
+            /anchor anchor 6 add def
+            anchor limit gt {
+                exit
+            } if
+            [ -1 1 ] {
+                anchor add candidate exch mod 0 eq {
+                    /prime false def
+                    exit
+                } if
+            } forall
+            prime false eq {
+                exit
+            } if
+        } loop
+        prime
+    } repeat
+    end
+} bind def
+
+
+% end included library code
+
+/binaryprefix {
+    0 dict begin
+    [ exch
+      /n 0 def
+      {
+          /n n 2 mul def
+          1 eq {
+              /n n 1 add def
+          } if
+          n isprime
+      } forall
+    ]
+    end
+} bind def
+
+(binaryprefix) test.start
+[1 0 1] binaryprefix [false true true] deepeq test
+[1 1 0] binaryprefix [false true false] deepeq test
+[1 1 1 1 0 1 0 0 0 0 1 0 1 0 0 1 0 0 0 1] binaryprefix [false true true false false true false false false false false false false false false false false false false true] deepeq test
+test.end
diff --git a/challenge-305/roger-bell-west/postscript/ch-2.ps b/challenge-305/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..68f1a70cc2
--- /dev/null
+++ b/challenge-305/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,318 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/map { % array proc -> array
+    2 dict begin
+    /p exch def
+    [ exch
+      {
+          p
+      } forall
+    ]
+    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
+
+/a2s {
+    2 dict begin
+    /i exch def
+    i length dup string /o exch def
+    1 sub 0 exch 1 exch {
+        dup i 3 -1 roll get o 3 1 roll put
+    } for
+    o
+    end
+} bind def
+
+/listmax {
+    { max } reduce
+} 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.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/s2a {
+    [ exch { } forall ]
+} bind def
+
+/quicksort.cmp {
+    2 copy
+    lt {
+        pop pop -1
+    } {
+        gt {
+            1
+        } {
+            0
+        } ifelse
+    } ifelse
+} 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
+
+/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
+
+/reduce { % array proc -> value
+    2 dict begin
+    /p exch def
+    /a exch def
+    a 0 get
+    1 1 a length 1 sub {
+        a exch get
+        p
+    } for
+    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
+
+/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
+
+/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
+
+/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_keygen { % [ a c b ] { keygen } -> [ a b c ]
+    3 dict begin
+    /kg exch def
+    /arr exch def
+    /kl << arr {
+                dup kg
+            } forall >> def
+    arr {
+        exch kl exch get exch kl exch get quicksort.cmp
+    } quicksort.with_comparator
+} bind def
+
+
+% end included library code
+
+/aliendictionary {
+    0 dict begin
+    /dc exch def
+    /a exch def
+    /mxl a { length } map listmax def
+    /dh 0 dict def
+    dc enumerate.array {
+        aload pop
+        /c exch def
+        /i exch def
+        dh c i 1 add put
+    } forall
+    /b a deepcopy def
+    /numerics 0 dict def
+    b {
+        /w exch def
+        /n 0 def
+        /cc w s2a { [ exch ] a2s } map def
+        0 1 mxl 1 sub {
+            /i exch def
+            /n n 27 mul def
+            i w length lt {
+                /n n dh cc i get get add def
+            } if
+        } for
+        numerics w n put
+    } forall
+    b { numerics exch get } quicksort.with_keygen
+    b
+    end
+} bind def
+
+(aliendictionary) test.start
+[(perl) (python) (raku)] [(h) (l) (a) (b) (y) (d) (e) (f) (g) (i) (r) (k) (m) (n) (o) (p) (q) (j) (s) (t) (u) (v) (w) (x) (c) (z)] aliendictionary [(raku) (python) (perl)] deepeq test
+[(the) (weekly) (challenge)] [(c) (o) (r) (l) (d) (a) (b) (t) (e) (f) (g) (h) (i) (j) (k) (m) (n) (p) (q) (s) (w) (u) (v) (x) (y) (z)] aliendictionary [(challenge) (the) (weekly)] deepeq test
+test.end
diff --git a/challenge-305/roger-bell-west/python/ch-1.py b/challenge-305/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..9b37ac4cda
--- /dev/null
+++ b/challenge-305/roger-bell-west/python/ch-1.py
@@ -0,0 +1,57 @@
+#! /usr/bin/python3
+
+def isqrt(s:int):
+  if s <= 1:
+    return s
+  x0 = s // 2
+  x1 = (x0 + s // x0) // 2
+  while x1 < x0:
+    x0 = x1
+    x1 = (x0 + s // x0) // 2
+  return x0
+
+def is_prime(candidate):
+  if candidate < 2:
+    return False
+  elif candidate==2:
+    return True
+  elif candidate==3:
+    return True
+  elif candidate % 2 == 0:
+    return False
+  elif candidate % 3 == 0:
+    return False
+  anchor = 0
+  limit = isqrt(candidate)
+  while True:
+    anchor += 6
+    for t in range(anchor-1,anchor+2,2):
+      if t > limit:
+        return True
+      if candidate % t == 0:
+        return False
+
+def binaryprefix(a):
+  out = []
+  n = 0
+  for x in a:
+    n *= 2
+    if x == 1:
+      n += 1
+    out.append(is_prime(n))
+  return out
+
+import unittest
+
+class TestBinaryprefix(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(binaryprefix([1, 0, 1]), [False, True, True], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(binaryprefix([1, 1, 0]), [False, True, False], 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(binaryprefix([1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]), [False, True, True, False, False, True, False, False, False, False, False, False, False, False, False, False, False, False, False, True], 'example 3')
+
+unittest.main()
diff --git a/challenge-305/roger-bell-west/python/ch-2.py b/challenge-305/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..af3d0a9bbd
--- /dev/null
+++ b/challenge-305/roger-bell-west/python/ch-2.py
@@ -0,0 +1,30 @@
+#! /usr/bin/python3
+
+def aliendictionary(a, dc):
+  mxl = max(len(x) for x in a)
+  dh = dict()
+  for i, c in enumerate(dc):
+    dh[c] = i + 1
+  b = a
+  numerics = dict()
+  for w in a:
+    n = 0
+    for i in range(mxl):
+      n *= 27
+      if i < len(w):
+        n += dh[w[i]]
+    numerics[w] = n
+  b.sort(key = lambda i: numerics[i])
+  return b
+
+import unittest
+
+class TestAliendictionary(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(aliendictionary(["perl", "python", "raku"], ["h", "l", "a", "b", "y", "d", "e", "f", "g", "i", "r", "k", "m", "n", "o", "p", "q", "j", "s", "t", "u", "v", "w", "x", "c", "z"]), ["raku", "python", "perl"], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(aliendictionary(["the", "weekly", "challenge"], ["c", "o", "r", "l", "d", "a", "b", "t", "e", "f", "g", "h", "i", "j", "k", "m", "n", "p", "q", "s", "w", "u", "v", "x", "y", "z"]), ["challenge", "the", "weekly"], 'example 2')
+
+unittest.main()
diff --git a/challenge-305/roger-bell-west/raku/ch-1.p6 b/challenge-305/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..d982bc772a
--- /dev/null
+++ b/challenge-305/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,51 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 3;
+
+is-deeply(binaryprefix([1, 0, 1]), [False, True, True], 'example 1');
+is-deeply(binaryprefix([1, 1, 0]), [False, True, False], 'example 2');
+is-deeply(binaryprefix([1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]), [False, True, True, False, False, True, False, False, False, False, False, False, False, False, False, False, False, False, False, True], 'example 3');
+
+sub is_prime($candidate) {
+    if (!is-prime($candidate)) {
+        return False;
+    } elsif ($candidate < 2) {
+        return False;
+    } elsif ($candidate==2) {
+        return True;
+    } elsif ($candidate==3) {
+        return True;
+    } elsif ($candidate % 2 == 0) {
+        return False;
+    } elsif ($candidate % 3 == 0) {
+        return False;
+    }
+    my $anchor=0;
+    my $limit=floor(sqrt($candidate));
+    while (True) {
+        $anchor+=6;
+        for ($anchor-1,$anchor+1) -> $t {
+            if ($t > $limit) {
+                return True;
+            }
+            if ($candidate % $t == 0) {
+                return False;
+            }
+        }
+    }
+}
+
+sub binaryprefix(@a) {
+    my @out;
+    my $n = 0;
+    for @a -> $x {
+        $n *= 2;
+        if ($x == 1) {
+            $n++;
+        }
+        @out.push(is_prime($n));
+    }
+    @out;
+}
diff --git a/challenge-305/roger-bell-west/raku/ch-2.p6 b/challenge-305/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..8012cd8a9f
--- /dev/null
+++ b/challenge-305/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,31 @@
+#! /usr/bin/raku
+
+use Test;
+
+plan 2;
+
+is-deeply(aliendictionary(['perl', 'python', 'raku'], ['h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z']), ['raku', 'python', 'perl'], 'example 1');
+is-deeply(aliendictionary(['the', 'weekly', 'challenge'], ['c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z']), ['challenge', 'the', 'weekly'], 'example 2');
+
+sub aliendictionary(@a, @dc) {
+  my $mxl = @a.map({$_.chars}).max;
+  my %dh;
+  for @dc.kv -> $i, $c {
+    %dh{$c} = $i + 1;
+  }
+  my @b = @a;
+  my %numerics;
+  for @b -> $w {
+    my $n = 0;
+    my @cc = $w.comb;
+    for 0 ..^ $mxl -> $i {
+      $n *= 27;
+      if ($i < $w.chars) {
+        $n += %dh{@cc[$i]};
+      }
+    }
+    %numerics{$w} = $n;
+  }
+  @b = @b.sort({ %numerics{$^a} <=> %numerics{$^b} });
+  return @b;
+}
diff --git a/challenge-305/roger-bell-west/ruby/ch-1.rb b/challenge-305/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..2eb63be3d2
--- /dev/null
+++ b/challenge-305/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,34 @@
+#! /usr/bin/ruby
+
+require 'prime'
+
+def binaryprefix(a)
+  out = []
+  n = 0
+  a.each do |x|
+    n *= 2
+    if x == 1
+      n += 1
+    end
+    out.push(n.prime?)
+  end
+  out
+end
+
+require 'test/unit'
+
+class TestBinaryprefix < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal([false, true, true], binaryprefix([1, 0, 1]))
+  end
+
+  def test_ex2
+    assert_equal([false, true, false], binaryprefix([1, 1, 0]))
+  end
+
+  def test_ex3
+    assert_equal([false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true], binaryprefix([1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]))
+  end
+
+end
diff --git a/challenge-305/roger-bell-west/ruby/ch-2.rb b/challenge-305/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..6f2db6d15d
--- /dev/null
+++ b/challenge-305/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,40 @@
+#! /usr/bin/ruby
+
+def aliendictionary(a, dc)
+  mxl = a.map { |x| x.length }.max
+  dh = Hash.new
+  dc.each_with_index do |c, i|
+    dh[c] = i
+  end
+  b = a
+  numerics = Hash.new
+  b.each do |w|
+    n = 0
+    cc = w.chars
+    0.upto(mxl - 1) do |i|
+      n *= 27
+      if i < w.length
+        n += dh[cc[i]]
+      end
+    end
+    numerics[w] = n
+  end
+  b.sort! do |i, j|
+    numerics[i] <=> numerics[j]
+  end
+  b
+end
+
+require 'test/unit'
+
+class TestAliendictionary < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(['raku', 'python', 'perl'], aliendictionary(['perl', 'python', 'raku'], ['h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z']))
+  end
+
+  def test_ex2
+    assert_equal(['challenge', 'the', 'weekly'], aliendictionary(['the', 'weekly', 'challenge'], ['c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z']))
+  end
+
+end
diff --git a/challenge-305/roger-bell-west/rust/ch-1.rs b/challenge-305/roger-bell-west/rust/ch-1.rs
new file mode 100755
index 0000000000..c47460e479
--- /dev/null
+++ b/challenge-305/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,70 @@
+#! /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!(binaryprefix(vec![1, 0, 1]), vec![false, true, true]);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(binaryprefix(vec![1, 1, 0]), vec![false, true, false]);
+}
+
+#[test]
+fn test_ex3() {
+    assert_eq!(binaryprefix(vec![1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1]), vec![false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true]);
+}
+
+fn isqrt(s: u32) -> u32 {
+    if s <= 1 {
+        return s;
+    }
+    let mut x0 = s / 2;
+    let mut x1 = (x0 + s / x0) / 2;
+    while x1 < x0 {
+        x0 = x1;
+        x1 = (x0 + s / x0) / 2;
+    }           
+    return x0;
+}
+
+fn is_prime(n: u32) -> bool {
+    if n == 1 {
+        return false;
+    }
+    if n>2 && n%2==0 {
+        return false;
+    }
+    if n>3 && n%3==0 {
+        return false;
+    }
+    let lim = isqrt(n);
+    let mut k6 = 0;
+    loop {
+        k6 += 6;
+        for t in [k6 - 1,k6 + 1] {
+            if t <= lim {
+                if n % t == 0 {
+                    return false;
+                }
+            } else {
+                return true;
+            }
+        }
+    }
+}
+
+fn binaryprefix(a: Vec<u8>) -> Vec<bool> {
+    let mut out = Vec::new();
+    let mut n = 0;
+    for x in a {
+        n *= 2;
+        if x == 1 {
+            n += 1;
+        }
+        out.push(is_prime(n));
+    }
+    out
+}
+
diff --git a/challenge-305/roger-bell-west/rust/ch-2.rs b/challenge-305/roger-bell-west/rust/ch-2.rs
new file mode 100755
index 0000000000..07bbd3cb26
--- /dev/null
+++ b/challenge-305/roger-bell-west/rust/ch-2.rs
@@ -0,0 +1,37 @@
+#! /bin/sh
+//usr/bin/env rustc --test $0 -o ${0}x && ./${0}x --nocapture; rm -f ${0}x ; exit
+
+use std::collections::HashMap;
+
+#[test]
+fn test_ex1() {
+    assert_eq!(aliendictionary(vec!["perl", "python", "raku"], vec!['h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z']), vec!["raku", "python", "perl"]);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(aliendictionary(vec!["the", "weekly", "challenge"], vec!['c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z']), vec!["challenge", "the", "weekly"]);
+}
+
+fn aliendictionary(a: Vec<&str>, dc: Vec<char>) -> Vec<String> {
+    let mxl = a.iter().map(|x| x.len()).max().unwrap();
+    let mut dh: HashMap<char, usize> = HashMap::new();
+    for (i, c) in dc.iter().enumerate() {
+        dh.insert(*c, i + 1);
+    }
+    let mut b = a.into_iter().map(|x| x.to_string()).collect::<Vec<String>>();
+    let mut numerics: HashMap<String, u64> = HashMap::new();
+    for w in &b {
+        let mut n = 0;
+        let cc = w.chars().collect::<Vec<char>>();
+        for i in 0 .. mxl {
+            n *= 27;
+            if i < w.len() {
+                n += *dh.get(&cc[i]).unwrap() as u64;
+            }
+        }
+        numerics.insert(w.clone(), n);
+    }
+    b.sort_by(|i, j| numerics.get(i).unwrap().cmp(&numerics.get(j).unwrap()));
+    b
+}
diff --git a/challenge-305/roger-bell-west/scala/ch-1.scala b/challenge-305/roger-bell-west/scala/ch-1.scala
new file mode 100644
index 0000000000..7be49568e1
--- /dev/null
+++ b/challenge-305/roger-bell-west/scala/ch-1.scala
@@ -0,0 +1,80 @@
+import scala.collection.mutable.ListBuffer
+
+object Binaryprefix {
+  def isqrt(s: Int): Int = {
+    if (s <= 1) {
+      return s
+    }
+    var x0 = s / 2
+    var x1 = (x0 + s / x0) / 2
+    while (x1 < x0) {
+      x0 = x1
+      x1 = (x0 + s / x0) / 2
+    }
+    return x0
+  }
+  def is_prime(n: Int): Boolean = {
+    var isprime = true
+    if (n == 1) {
+      isprime = false
+    }
+    if (n > 2 && n % 2 == 0) {
+      isprime = false
+    }
+    if (n > 3 && n % 3 == 0) {
+      isprime = false
+    }
+    if (isprime) {
+      val lim = isqrt(n)
+      var k6 = 0
+      var cnt = true
+      while (cnt) {
+        k6 += 6
+        for (t <- List(k6 - 1, k6 + 1)) {
+          if (t <= lim) {
+            if (n % t == 0) {
+              isprime = false
+              cnt = false
+            }
+          } else {
+            cnt = false
+          }
+        }
+      }
+    }
+    isprime
+  }
+  def binaryprefix(a: List[Int]): List[Boolean] = {
+    var out = new ListBuffer[Boolean]
+    var n = 0
+    for (x <- a) {
+      n *= 2
+      if (x == 1) {
+        n += 1
+      }
+      out += is_prime(n)
+    }
+    out.toList
+  }
+  def main(args: Array[String]) {
+    if (binaryprefix(List(1, 0, 1)) == List(false, true, true)) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    print(" ")
+    if (binaryprefix(List(1, 1, 0)) == List(false, true, false)) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    print(" ")
+    if (binaryprefix(List(1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1)) == List(false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true)) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    println("")
+
+  }
+}
diff --git a/challenge-305/roger-bell-west/scala/ch-2.scala b/challenge-305/roger-bell-west/scala/ch-2.scala
new file mode 100644
index 0000000000..b65294d23b
--- /dev/null
+++ b/challenge-305/roger-bell-west/scala/ch-2.scala
@@ -0,0 +1,41 @@
+import scala.collection.mutable
+
+object Aliendictionary {
+  def aliendictionary(a: List[String], dc: List[Char]): List[String] = {
+    val mxl = a.map(x => x.length).max
+    var dh = mutable.Map.empty[Char, Int]
+    for ((c, i) <- dc.zipWithIndex) {
+      dh += (c -> i)
+    }
+    var numerics = mutable.Map.empty[String, Long]
+    for (w <- a) {
+      var n = 0.toLong
+      val cc = w.toList
+      for (i <- 0 until mxl) {
+        n *= 27.toLong
+        if (i < w.length) {
+          n += dh(cc(i)).toLong
+        }
+      }
+      numerics += (w -> n)
+    }
+    a.sortWith((i, j) => {
+      numerics(i) < numerics(j)
+    })
+  }
+  def main(args: Array[String]) {
+    if (aliendictionary(List("perl", "python", "raku"), List('h', 'l', 'a', 'b', 'y', 'd', 'e', 'f', 'g', 'i', 'r', 'k', 'm', 'n', 'o', 'p', 'q', 'j', 's', 't', 'u', 'v', 'w', 'x', 'c', 'z')) == List("raku", "python", "perl")) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    print(' ')
+    if (aliendictionary(List("the", "weekly", "challenge"), List('c', 'o', 'r', 'l', 'd', 'a', 'b', 't', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'q', 's', 'w', 'u', 'v', 'x', 'y', 'z')) == List("challenge", "the", "weekly")) {
+      print("Pass")
+    } else {
+      print("Fail")
+    }
+    println("")
+
+  }
+}
diff --git a/challenge-305/roger-bell-west/tests.json b/challenge-305/roger-bell-west/tests.json
new file mode 100644
index 0000000000..2b66369498
--- /dev/null
+++ b/challenge-305/roger-bell-west/tests.json
@@ -0,0 +1,36 @@
+{
+    "ch-1" : [
+        {
+            "function" : "binaryprefix",
+            "arguments" : [ 1, 0, 1 ],
+            "result" : [ false, true, true ]
+        },
+        {
+            "arguments" : [ 1, 1, 0 ],
+            "result" : [ false, true, false ]
+        },
+        {
+            "arguments" : [ 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1 ],
+            "result" : [ false, true, true, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, true ]
+        }
+    ],
+    "ch-2" : [
+        {
+            "function" : "aliendictionary",
+            "multiarg" : true,
+            "arguments" : [
+                [ "perl", "python", "raku" ],
+                [ "h", "l", "a", "b", "y", "d", "e", "f", "g", "i", "r", "k", "m", "n", "o", "p", "q", "j", "s", "t", "u", "v", "w", "x", "c", "z" ]
+            ],
+            "result" : [ "raku", "python", "perl" ]
+        },
+        {
+            "multiarg" : true,
+            "arguments" : [
+                [ "the", "weekly", "challenge" ],
+                [ "c", "o", "r", "l", "d", "a", "b", "t", "e", "f", "g", "h", "i", "j", "k", "m", "n", "p", "q", "s", "w", "u", "v", "x", "y", "z" ]
+            ],
+            "result" : [ "challenge", "the", "weekly" ]
+        }
+    ]
+}
-- 
cgit