Merge pull request #6732 from Firedrake/rogerbw-challenge-182

Solutions for challenge #182

18 files changed, 855 insertions, 0 deletions

diff --git a/challenge-182/roger-bell-west/javascript/ch-1.js b/challenge-182/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..b181eb81c2
--- /dev/null
+++ b/challenge-182/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,36 @@
+#! /usr/bin/node
+
+"use strict"
+
+function maxindex(n) {
+    let mxv = 0;
+    let mxi = 0;
+    n.forEach((v, i) => {
+        if (i == 0 || v > mxv) {
+            mxv = v;
+            mxi = i;
+        }
+    });
+    return mxi;
+}
+
+if (maxindex([5, 2, 9, 1, 7, 6]) == 2) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+
+if (maxindex([4, 2, 3, 1, 5, 0]) == 4) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+
+if (maxindex([4, 2, 3, 1, 4, 0]) == 0) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-182/roger-bell-west/javascript/ch-2.js b/challenge-182/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..0afcc2751f
--- /dev/null
+++ b/challenge-182/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,42 @@
+#! /usr/bin/node
+
+"use strict"
+
+function commonpath(p) {
+    let pa = [];
+    let pl = [];
+    for (let sp of p) {
+        let q = sp.split("/");
+        pl.push(q.length);
+        pa.push(q);
+    }
+    let out = [];
+    for (let cl = 0; cl < Math.min(...pl); cl++) {
+        let ex = false;
+        let tx = pa[0][cl];
+        for (let pe of pa) {
+            if (pe[cl] != tx) {
+                ex = true;
+                break;
+            }
+        }
+        if (ex) {
+            break;
+        }
+        out.push(tx);
+    }
+    return out.join("/");
+}
+
+if (commonpath([
+    "/a/b/c/1/x.pl",
+    "/a/b/c/d/e/2/x.pl",
+    "/a/b/c/d/3/x.pl",
+    "/a/b/c/4/x.pl",
+    "/a/b/c/d/5/x.pl"
+]) == "/a/b/c") {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-182/roger-bell-west/kotlin/ch-1.kt b/challenge-182/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..3dcb228086
--- /dev/null
+++ b/challenge-182/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,32 @@
+fun maxindex(n: List<Int>): Int {
+    var mxv = 0;
+    var mxi = 0;
+    for ((i, v) in n.withIndex()) {
+        if (i == 0 || v > mxv) {
+            mxv = v
+            mxi = i
+        }
+    }
+    return mxi
+}
+
+fun main() {
+    if (maxindex(listOf(5, 2, 9, 1, 7, 6)) == 2) {
+        print("Pass")
+    } else {
+        print("FAIL")
+    }
+    print(" ")
+    if (maxindex(listOf(4, 2, 3, 1, 5, 0)) == 4) {
+        print("Pass")
+    } else {
+        print("FAIL")
+    }
+    print(" ")
+    if (maxindex(listOf(4, 2, 3, 1, 4, 0)) == 0) {
+        print("Pass")
+    } else {
+        print("FAIL")
+    }
+    println("")
+}
diff --git a/challenge-182/roger-bell-west/kotlin/ch-2.kt b/challenge-182/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..914808fa33
--- /dev/null
+++ b/challenge-182/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,40 @@
+fun commonpath(p: List<String>): String {
+    var pa = ArrayList<List<String>>()
+    var pl = ArrayList<Int>()
+    for (sp in p) {
+        val q = sp.split("/").toList()
+        pa.add(q)
+        pl.add(q.size)
+    }
+    var out = ArrayList<String>()
+    for (cl in 0..pl.minOrNull()!!-1) {
+        var ex = false
+        val tx = pa[0][cl]
+        for (pe in pa) {
+            if (pe[cl] != tx) {
+                ex = true
+                break
+            }
+        }
+        if (ex) {
+            break
+        }
+        out.add(tx)
+    }
+    return out.joinToString("/")
+}
+
+fun main() {
+    if (commonpath(listOf(
+                       "/a/b/c/1/x.pl",
+                       "/a/b/c/d/e/2/x.pl",
+                       "/a/b/c/d/3/x.pl",
+                       "/a/b/c/4/x.pl",
+                       "/a/b/c/d/5/x.pl"
+        )) == "/a/b/c") {
+        print("Pass")
+    } else {
+        print("FAIL")
+    }
+    println("")
+}
diff --git a/challenge-182/roger-bell-west/lua/ch-1.lua b/challenge-182/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..5e1e0c4887
--- /dev/null
+++ b/challenge-182/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,34 @@
+#! /usr/bin/lua
+
+function maxindex(n)
+   local mxv = 0
+   local mxi = 0
+   for i, v in ipairs(n) do
+      if i == 1 or v > mxv then
+         mxv = v
+         mxi = i
+      end
+   end
+   return mxi-1
+end
+
+if maxindex({5, 2, 9, 1, 7, 6}) == 2 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+io.write(" ")
+
+if maxindex({4, 2, 3, 1, 5, 0}) == 4 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+io.write(" ")
+
+if maxindex({4, 2, 3, 1, 4, 0}) == 0 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+print("")
diff --git a/challenge-182/roger-bell-west/lua/ch-2.lua b/challenge-182/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..08c63996aa
--- /dev/null
+++ b/challenge-182/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,53 @@
+#! /usr/bin/lua
+
+-- bart at https://stackoverflow.com/questions/1426954/split-string-in-lua
+function split(inputstr, sep)
+   sep=sep or '%s'
+   local t={}
+   for field,s in string.gmatch(inputstr, "([^"..sep.."]*)("..sep.."?)") do
+      table.insert(t,field)
+      if s=="" then
+         return t
+      end
+   end
+end
+   
+
+function commonpath(p)
+   local pa = {}
+   local pl = {}
+   for i, sp in ipairs(p) do
+      local q = split(sp, "/")
+      table.insert(pl,#q)
+      table.insert(pa,q)
+   end
+   local out = {}
+   for cl = 1,math.min(table.unpack(pl)) do
+      local ex = false
+      local tx = pa[1][cl]
+      for i, pe in ipairs(pa) do
+         if pe[cl] ~= tx then
+            ex = true
+            break
+         end
+      end
+      if ex then
+         break
+      end
+      table.insert(out,tx)
+   end
+   return table.concat(out,"/")
+end
+
+if commonpath({
+      "/a/b/c/1/x.pl",
+      "/a/b/c/d/e/2/x.pl",
+      "/a/b/c/d/3/x.pl",
+      "/a/b/c/4/x.pl",
+      "/a/b/c/d/5/x.pl"
+             }) == "/a/b/c" then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+print("")
diff --git a/challenge-182/roger-bell-west/perl/ch-1.pl b/challenge-182/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..6a2d333f49
--- /dev/null
+++ b/challenge-182/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,23 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 3;
+
+is(maxindex([5, 2, 9, 1, 7, 6]),2,'example 1');
+is(maxindex([4, 2, 3, 1, 5, 0]),4,'example 2');
+is(maxindex([4, 2, 3, 1, 4, 0]),0,'example 3');
+
+sub maxindex($n) {
+  my $mxv = 0;
+  my $mxi = 0;
+  foreach my $i (0..$#{$n}) {
+    if ($i == 0 || $n->[$i] > $mxv) {
+      $mxv = $n->[$i];
+      $mxi = $i;
+    }
+  }
+  return $mxi;
+}
diff --git a/challenge-182/roger-bell-west/perl/ch-2.pl b/challenge-182/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..8da4c02792
--- /dev/null
+++ b/challenge-182/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,43 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 1;
+
+use List::Util qw(min);
+
+is(commonpath([
+  "/a/b/c/1/x.pl",
+  "/a/b/c/d/e/2/x.pl",
+  "/a/b/c/d/3/x.pl",
+  "/a/b/c/4/x.pl",
+  "/a/b/c/d/5/x.pl"
+    ]), "/a/b/c", 'example 1');
+
+sub commonpath($p) {
+  my @pa;
+  my @pl;
+  foreach my $sp (@{$p}) {
+    my @q = split '/',$sp;
+    push @pl,scalar @q;
+    push @pa,\@q;
+  }
+  my @out;
+  foreach my $cl (0..min(@pl)-1) {
+    my $ex = 0;
+    my $tx = $pa[0][$cl];
+    foreach my $pe (@pa) {
+      if ($pe->[$cl] ne $tx) {
+        $ex = 1;
+        last;
+      }
+    }
+    if ($ex) {
+      last;
+    }
+    push @out,$tx;
+  }
+  return join('/',@out);
+}
diff --git a/challenge-182/roger-bell-west/postscript/ch-1.ps b/challenge-182/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..d8835bb397
--- /dev/null
+++ b/challenge-182/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,70 @@
+%!PS
+
+% begin included library code
+% see https://github.com/Firedrake/postscript-libraries/
+/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
+
+/enumerate.array {
+    1 dict begin
+    /a exch def
+    [
+      0 1 a length 1 sub {
+          [ exch dup a exch get ]
+      } for
+    ]
+    end
+} bind def
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+
+% end included library code
+
+/maxindex {
+    4 dict begin
+    /mxv 0 def
+    /mxi 0 def
+    enumerate.array {
+        dup 0 get /i exch def
+        1 get /v exch def
+        i 0 eq v mxv gt or {
+            /mxv v def
+            /mxi i def
+        } if
+    } forall
+    mxi
+    end
+} bind def
+
+(maxindex) test.start
+[5 2 9 1 7 6] maxindex 2 eq test
+[4 2 3 1 5 0] maxindex 4 eq test
+[4 2 3 1 4 0] maxindex 0 eq test
+test.end
diff --git a/challenge-182/roger-bell-west/postscript/ch-2.ps b/challenge-182/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..323b3d9cda
--- /dev/null
+++ b/challenge-182/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,210 @@
+%!PS
+
+% begin included library code
+% see https://github.com/Firedrake/postscript-libraries/
+/apush.right { % [a b] c -> [a b c]
+    exch
+    [ exch aload length 2 add -1 roll ]
+} 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
+
+/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
+
+/listmin {
+    { min } reduce
+} 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
+
+/apush { apush.right } bind def
+
+/strconcat % (a) (b) -> (ab)  
+{ exch dup length
+  2 index length add string
+  dup dup 4 2 roll copy length
+  4 -1 roll putinterval
+} bind def
+
+/strsplit % (ajbjc) (j) -> [ (a) (b) (c) ]
+{
+    1 dict begin
+    /sep exch def
+    [ exch
+      {
+          dup length 0 eq {
+              pop
+              exit
+          } {
+              sep search {
+                  exch pop
+                  dup length 0 eq {
+                      pop
+                  } {
+                      exch
+                  } ifelse
+              } {
+                  ()
+              } ifelse
+          } ifelse
+      } loop
+    ]
+    end
+} bind def
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/strjoin % [(a) (b) (c)] (j) -> (ajbjc)
+{
+    3 dict begin
+    /j exch def
+    dup 0 get /out exch def
+    /first true def
+    {
+        first {
+            pop
+            /first false def
+        } {
+            out j strconcat
+            exch strconcat
+            /out exch def
+        } ifelse
+    } forall
+    out
+    end
+} bind def
+
+
+% end included library code
+
+/commonpath {
+    6 dict begin
+    /pa 0 array def
+    /pl 0 array def
+    {
+        (/) strsplit /q exch def
+        /pl pl q length apush def
+        /pa pa q apush def
+    } forall
+    /out [ () ] def
+    0 1 pl listmin 1 sub {
+        /cl exch def
+        /ex false def
+        /tx pa 0 get cl get def
+        pa {
+            cl get tx deepeq not {
+                /ex true def
+                exit
+            } if
+        } forall
+        ex {
+            exit
+        } if
+        /out out tx apush def
+    } for
+    out (/) strjoin
+    end
+} bind def
+
+(commonpath) test.start
+[
+    (/a/b/c/1/x.pl)
+    (/a/b/c/d/e/2/x.pl)
+    (/a/b/c/d/3/x.pl)
+    (/a/b/c/4/x.pl)
+    (/a/b/c/d/5/x.pl)
+] commonpath (/a/b/c) deepeq test
+test.end
diff --git a/challenge-182/roger-bell-west/python/ch-1.py b/challenge-182/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..cd935671c9
--- /dev/null
+++ b/challenge-182/roger-bell-west/python/ch-1.py
@@ -0,0 +1,28 @@
+#! /usr/bin/python3
+
+import unittest
+
+def maxindex(n):
+  mxv = 0
+  mxi = 0
+  for (i, v) in enumerate(n):
+    if i == 0 or v > mxv:
+      mxv = v
+      mxi = i
+  return mxi
+
+class TestMaxindex(unittest.TestCase):
+
+        def test_ex1(self):
+          self.assertEqual(maxindex([5, 2, 9, 1, 7, 6]),
+                           2, 'example 1')
+
+        def test_ex2(self):
+          self.assertEqual(maxindex([4, 2, 3, 1, 5, 0]),
+                           4, 'example 2')
+
+        def test_ex3(self):
+          self.assertEqual(maxindex([4, 2, 3, 1, 4, 0]),
+                           0, 'example 3')
+
+unittest.main()
diff --git a/challenge-182/roger-bell-west/python/ch-2.py b/challenge-182/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..c06b97aedb
--- /dev/null
+++ b/challenge-182/roger-bell-west/python/ch-2.py
@@ -0,0 +1,39 @@
+#! /usr/bin/python3
+
+from collections import defaultdict
+
+import unittest
+
+def commonpath(p):
+  pa = []
+  pl = []
+  for sp in p:
+    q = sp.split("/")
+    pl.append(len(q))
+    pa.append(q)
+  out = []
+  for cl in range(min(pl)):
+    ex = False
+    tx = pa[0][cl]
+    for pe in pa:
+      if pe[cl] != tx:
+        ex = True
+        break
+    if ex:
+      break
+    out.append(tx)
+  return "/".join(out)
+
+class TestCommonpath(unittest.TestCase):
+
+        def test_ex1(self):
+          self.assertEqual(commonpath([
+            "/a/b/c/1/x.pl",
+            "/a/b/c/d/e/2/x.pl",
+            "/a/b/c/d/3/x.pl",
+            "/a/b/c/4/x.pl",
+            "/a/b/c/d/5/x.pl"
+          ]),
+                           "/a/b/c", 'example 1')
+
+unittest.main()
diff --git a/challenge-182/roger-bell-west/raku/ch-1.p6 b/challenge-182/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..10b2112122
--- /dev/null
+++ b/challenge-182/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,21 @@
+#! /usr/bin/perl6
+
+use Test;
+
+plan 3;
+
+is(maxindex([5, 2, 9, 1, 7, 6]),2,'example 1');
+is(maxindex([4, 2, 3, 1, 5, 0]),4,'example 2');
+is(maxindex([4, 2, 3, 1, 4, 0]),0,'example 3');
+
+sub maxindex(@n) {
+    my $mxv = 0;
+    my $mxi = 0;
+    for (0..@n.end) -> $i {
+        if ($i == 0 || @n[$i] > $mxv) {
+            $mxv = @n[$i];
+            $mxi = $i;
+        }
+    }
+    return $mxi;
+}
diff --git a/challenge-182/roger-bell-west/raku/ch-2.p6 b/challenge-182/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..97f93f8492
--- /dev/null
+++ b/challenge-182/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,39 @@
+#! /usr/bin/perl6
+
+use Test;
+
+plan 1;
+
+is(commonpath([
+                     "/a/b/c/1/x.pl",
+                     "/a/b/c/d/e/2/x.pl",
+                     "/a/b/c/d/3/x.pl",
+                     "/a/b/c/4/x.pl",
+                     "/a/b/c/d/5/x.pl"
+                 ]), "/a/b/c", 'example 1');
+
+sub commonpath(@p) {
+    my @pa;
+    my @pl;
+    for @p -> $sp {
+        my @q = split("/",$sp);
+        @pl.push(@q.elems);
+        @pa.push(@q);
+    }
+    my @out;
+    for (0..min(@pl)-1) -> $cl {
+        my $ex = False;
+        my $tx = @pa[0][$cl];
+        for (@pa) -> @pe {
+            if (@pe[$cl] ne $tx) {
+                $ex = True;
+                last;
+            }
+        }
+        if ($ex) {
+            last;
+        }
+        @out.push($tx);
+    }
+    return @out.join("/");
+}
diff --git a/challenge-182/roger-bell-west/ruby/ch-1.rb b/challenge-182/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..5863f966ea
--- /dev/null
+++ b/challenge-182/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,31 @@
+#! /usr/bin/ruby
+
+require 'test/unit'
+
+def maxindex(n)
+  mxv = 0
+  mxi = 0
+  n.each_with_index do |v, i|
+    if i == 0 || v > mxv then
+      mxv = v
+      mxi = i
+    end
+  end
+  return mxi
+end
+
+class TestMaxindex < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(2, maxindex([5, 2, 9, 1, 7, 6]))
+  end
+
+  def test_ex2
+    assert_equal(4, maxindex([4, 2, 3, 1, 5, 0]))
+  end
+
+  def test_ex3
+    assert_equal(0, maxindex([4, 2, 3, 1, 4, 0]))
+  end
+
+end
diff --git a/challenge-182/roger-bell-west/ruby/ch-2.rb b/challenge-182/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..43ffba95e5
--- /dev/null
+++ b/challenge-182/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,43 @@
+#! /usr/bin/ruby
+
+require 'test/unit'
+
+def commonpath(p)
+  pa = []
+  pl = []
+  p.each do |sp|
+    q = sp.split("/")
+    pl.push(q.length)
+    pa.push(q)
+  end
+  out = []
+  0.upto(pl.min-1).each do |cl|
+    ex = false
+    tx = pa[0][cl]
+    pa.each do |pe|
+      if pe[cl] != tx then
+        ex = true
+        break
+      end
+    end
+    if ex then
+      break
+    end
+    out.push(tx)
+  end
+  return out.join("/")
+end
+
+class TestCommonpath < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal("/a/b/c", commonpath([
+                                        "/a/b/c/1/x.pl",
+                                        "/a/b/c/d/e/2/x.pl",
+                                        "/a/b/c/d/3/x.pl",
+                                        "/a/b/c/4/x.pl",
+                                        "/a/b/c/d/5/x.pl"
+                                      ]))
+  end
+
+end
diff --git a/challenge-182/roger-bell-west/rust/ch-1.rs b/challenge-182/roger-bell-west/rust/ch-1.rs
new file mode 100755
index 0000000000..3820a782ca
--- /dev/null
+++ b/challenge-182/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,29 @@
+#! /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!(maxindex(vec![5, 2, 9, 1, 7, 6]), 2);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(maxindex(vec![4, 2, 3, 1, 5, 0]), 4);
+}
+
+#[test]
+fn test_ex3() {
+    assert_eq!(maxindex(vec![4, 2, 3, 1, 4, 0]), 0);
+}
+
+fn maxindex(n: Vec<isize>) -> usize {
+    let mut mxv = 0;
+    let mut mxi = 0;
+    for (i, v) in n.iter().enumerate() {
+        if i == 0 || *v > mxv {
+            mxv = *v;
+            mxi = i;
+        }
+    }
+    mxi
+}
diff --git a/challenge-182/roger-bell-west/rust/ch-2.rs b/challenge-182/roger-bell-west/rust/ch-2.rs
new file mode 100755
index 0000000000..06b6abe5eb
--- /dev/null
+++ b/challenge-182/roger-bell-west/rust/ch-2.rs
@@ -0,0 +1,42 @@
+#! /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!(
+        commonpath(vec![
+            "/a/b/c/1/x.pl",
+            "/a/b/c/d/e/2/x.pl",
+            "/a/b/c/d/3/x.pl",
+            "/a/b/c/4/x.pl",
+            "/a/b/c/d/5/x.pl"
+        ]),
+        "/a/b/c"
+    );
+}
+
+fn commonpath(p: Vec<&str>) -> String {
+    let mut pa: Vec<Vec<String>> = Vec::new();
+    let mut pl: Vec<usize> = Vec::new();
+    for sp in p {
+        let q = sp.split('/').map(|x| x.to_string()).collect::<Vec<String>>();
+        pl.push(q.len());
+        pa.push(q);
+    }
+    let mut out: Vec<String> = Vec::new();
+    for cl in 0..*pl.iter().min().unwrap() {
+        let mut ex = false;
+        let tx = &pa[0][cl];
+        for pe in &pa {
+            if &pe[cl] != tx {
+                ex = true;
+                break;
+            }
+        }
+        if ex {
+            break;
+        }
+        out.push(tx.to_string());
+    }
+    out.join("/")
+}