Merge pull request #5623 from Firedrake/rogerbw-challenge-151

Solutions for challenge #151

18 files changed, 943 insertions, 0 deletions

diff --git a/challenge-151/roger-bell-west/javascript/ch-1.js b/challenge-151/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..3d8678e3a6
--- /dev/null
+++ b/challenge-151/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,66 @@
+#! /usr/bin/node
+
+function str2tree (st) {
+    let o=[0];
+    let d=0;
+    let p=0;
+    for (let e of st.match(/\S+/g)) {
+        if (e == "|") {
+            d++;
+            p=0;
+            m=(1<<(d+1))-1;
+            while (o.length < m) {
+                o.push(0);
+            }
+        } else {
+            let y=0;
+            if (e != "*") {
+                y=e;
+            }
+            let i=(1<<d) -1 +p;
+            o[i]=y;
+            p++;
+        }
+    }
+    return o;
+}
+
+function mindepth(tree) {
+    let firstleaf=tree.length;
+    for (let i=0; i < tree.length; i++) {
+        if (tree[i]==0) {
+            continue;
+        } else if ((i+1) << 1 >= tree.length ) {
+            firstleaf=i;
+            break;
+        } else {
+            let ni=((i+1) << 1)-1;
+            if (tree[ni]==0 && tree[ni+1]==0) {
+                firstleaf=i;
+                break;
+            }
+        }
+    }
+    let t=firstleaf+1;
+    let d=0;
+    while (t>0) {
+        t >>= 1;
+        d++;
+    }
+    return d;
+}
+
+if (mindepth(str2tree("1 | 2 3 | 4 5")) == 2) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+
+if (mindepth(str2tree("1 | 2 3 | 4 *  * 5 | * 6")) == 3) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
+
diff --git a/challenge-151/roger-bell-west/javascript/ch-2.js b/challenge-151/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..ebe3509d49
--- /dev/null
+++ b/challenge-151/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,43 @@
+#! /usr/bin/node
+
+function plan(houses) {
+    let terminal=houses.length-2;
+    let b=[[0]];
+    let reward=0;
+    while (b.length > 0) {
+        let c=b.pop();
+        let c1=c[c.length-1];
+        if (c1 >= terminal) {
+            let r=c.reduce((x,y) => x+houses[y],0);
+            if (r > reward) {
+                reward = r;
+            }
+        } else {
+            for (let n=c1+2; n <= c1+3; n++) {
+                if (n >= houses.length) {
+                    break;
+                }
+                let j=[...c];
+                j.push(n);
+                b.push(j);
+            }
+        }
+    }
+    return reward;
+}
+
+
+if (plan([2, 4, 5]) == 7) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+
+if (plan([4, 2, 3, 6, 5, 3]) == 13) {
+    process.stdout.write("Pass");
+} else {
+    process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
+
diff --git a/challenge-151/roger-bell-west/kotlin/ch-1.kt b/challenge-151/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..74704a596c
--- /dev/null
+++ b/challenge-151/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,65 @@
+fun str2tree(st: String): ArrayList<Int> {
+    var o=ArrayList<Int>()
+    o.add(0)
+    var d=0
+    var p=0
+    for (e in st.split(" ")) {
+        if (e == "|") {
+            d += 1
+            p = 0
+            val m = (1 shl (d+1)) -1
+            while (o.size < m) {
+                o.add(0)
+            }
+        } else {
+            var y=0
+            if (e != "*") {
+                y = e.toInt()
+            }
+            val i=(1 shl d) -1 +p
+            o[i] = y
+            p += 1
+        }
+    }
+    return o
+}
+
+fun mindepth(tree: ArrayList<Int>): Int {
+    var firstleaf=tree.size
+    for ((i, e) in tree.withIndex()) {
+        if (e == 0) {
+            continue
+        } else if ((i+1) shl 1 >= tree.size) {
+            firstleaf = i
+            break
+        } else {
+            val ni=((i+1) shl 1)-1
+            if (tree[ni]==0 && tree[ni+1] == 0) {
+                firstleaf = i
+                break
+            }
+        }
+    }
+    firstleaf += 1
+    var d=0
+    while (firstleaf > 0) {
+        firstleaf = firstleaf shr 1
+        d += 1
+    }
+    return d
+}
+
+fun main() {
+  if (mindepth(str2tree("1 | 2 3 | 4 5")) == 2) {
+    print("Pass")
+  } else {
+    print("FAIL")
+  }
+  print(" ")
+  if (mindepth(str2tree("1 | 2 3 | 4 * * 5 | * 6")) == 3) {
+    print("Pass")
+  } else {
+    print("FAIL")
+  }
+  println("")
+}
diff --git a/challenge-151/roger-bell-west/kotlin/ch-2.kt b/challenge-151/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..1ffef678e3
--- /dev/null
+++ b/challenge-151/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,45 @@
+fun plan(houses: List<Int>): Int {
+    val terminal=houses.size-2
+    var b=ArrayList<ArrayList<Int>>();
+    run {
+        var cx=ArrayList<Int>();
+        cx.add(0)
+        b.add(cx)
+    }
+    var reward=0
+    while (b.size > 0) {
+        val c=b.removeLast()
+        val c1=c[c.size-1]
+        if (c1 >= terminal) {
+            val r=c.map {houses[it]}.sum()
+            if (r > reward) {
+                reward=r
+            }
+        } else {
+            for (n in c1+2..c1+3) {
+                if (n >= houses.size) {
+                    break
+                }
+                var j=ArrayList(c)
+                j.add(n)
+                b.add(j)
+            }
+        }
+    }
+    return reward
+}
+
+fun main() {
+  if (plan(listOf(2, 4, 5)) == 7) {
+    print("Pass")
+  } else {
+    print("FAIL")
+  }
+  print(" ")
+  if (plan(listOf(4, 2, 3, 6, 5, 3)) == 13) {
+    print("Pass")
+  } else {
+    print("FAIL")
+  }
+  println("")
+}
diff --git a/challenge-151/roger-bell-west/lua/ch-1.lua b/challenge-151/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..a24ded8dd9
--- /dev/null
+++ b/challenge-151/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,63 @@
+#! /usr/bin/lua
+
+function str2tree(st)
+   local o = {}
+   local d = 0
+   local p = 0
+   for e in string.gmatch(st, "[^%s]+") do
+      if e == "|" then
+         d = d + 1
+         p = 0
+         local m = (1 << (d + 1)) - 1
+         while #o < m do
+            table.insert(o,0)
+         end
+      else
+         local y=0
+         if e ~= "*" then
+            y=0+e
+         end
+         local i = (1 << d) + p
+         o[i]=y
+         p = p + 1
+      end
+   end
+   return o
+end
+
+function mindepth(tree)
+   firstleaf=#tree+1
+   for i,e in ipairs(tree) do
+      if e == 0 then
+      elseif i << 1 > #tree then
+         firstleaf=i
+         break
+      else
+         ni=i << 1
+         if tree[ni] == 0 and tree[ni+1]==0 then
+            firstleaf=i
+            break
+         end
+      end
+   end
+   d=0
+   while firstleaf > 0 do
+      firstleaf = firstleaf >> 1
+      d = d + 1
+   end
+   return d
+end
+
+if mindepth(str2tree("1 | 2 3 | 4 5")) == 2 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+io.write(" ")
+
+if mindepth(str2tree("1 | 2 3 | 4 *  * 5 | * 6")) == 3 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+print("")
diff --git a/challenge-151/roger-bell-west/lua/ch-2.lua b/challenge-151/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..bedb953a2e
--- /dev/null
+++ b/challenge-151/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,47 @@
+#! /usr/bin/lua
+
+function plan(houses)
+   local terminal=#houses-1
+   local b={{1}}
+   local reward=0
+   while #b > 0 do
+      local c=b[#b]
+      b[#b]=nil
+      if c[#c] >= terminal then
+         local r=0
+         for k,v in pairs(c) do
+            r = r + houses[v]
+         end
+         if r > reward then
+            reward=r
+         end
+      else
+         for n = c[#c]+2,c[#c]+3 do
+            if n > #houses then
+               break
+            end
+            local j={}
+            for i,v in ipairs(c) do
+               table.insert(j,v)
+            end
+            table.insert(j,n)
+            table.insert(b,j)
+         end
+      end
+   end
+   return reward
+end
+
+if plan({2, 4, 5}) == 7 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+io.write(" ")
+
+if plan({4, 2, 3, 6, 5, 3}) == 13 then
+   io.write("Pass")
+else
+   io.write("FAIL")
+end
+print("")
diff --git a/challenge-151/roger-bell-west/perl/ch-1.pl b/challenge-151/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..b91c521dad
--- /dev/null
+++ b/challenge-151/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,62 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+use Test::More tests => 2;
+
+is(mindepth(str2tree("1 | 2 3 | 4 5")),2,'example 1');
+
+is(mindepth(str2tree("1 | 2 3 | 4 *  * 5 | * 6")),3,'example 2');
+
+sub str2tree {
+  my $st=shift;
+  my @o;
+  my $d=0;
+  my $p=0;
+  foreach my $e (split ' ',$st) {
+    if ($e eq '|') {
+      $d++;
+      $p=0;
+      my $m=(1<<($d+1))-1;
+      if (scalar @o < $m) {
+        push @o,(0) x ($m - scalar @o);
+      }
+    } else {
+      my $y=0;
+      if ($e ne '*') {
+        $y=0+$e;
+      }
+      my $i=(1<<$d) -1 +$p;
+      $o[$i]=$y;
+      $p++;
+    }
+  }
+  return \@o;
+}
+
+sub mindepth {
+  my $tree = shift;
+  my $firstleaf=scalar @{$tree};
+  foreach my $i (0..$#{$tree}) {
+    if ($tree->[$i]==0) {
+      next;
+    } elsif (($i+1) << 1 >= scalar @{$tree}) {
+      $firstleaf=$i;
+      last;
+    } else {
+      my $ni=(($i+1) << 1)-1;
+      if ($tree->[$ni]==0 && $tree->[$ni+1]==0) {
+        $firstleaf=$i;
+        last;
+      }
+    }
+  }
+  my $t=$firstleaf+1;
+  my $d=0;
+  while ($t > 0) {
+    $t >>= 1;
+    $d++;
+  }
+  return $d;
+}
diff --git a/challenge-151/roger-bell-west/perl/ch-2.pl b/challenge-151/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..98f69d92f5
--- /dev/null
+++ b/challenge-151/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,33 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+
+use Test::More tests => 2;
+
+is(planloot([2, 4, 5]),7,'example 1');
+
+is(planloot([4, 2, 3, 6, 5, 3]),13,'example 2');
+
+use List::Util qw(sum max);
+
+sub planloot {
+  my $houses = shift;
+  my $terminal=scalar @{$houses}-2;
+  my @b=([0]);
+  my $reward=0;
+  while (scalar @b > 0) {
+    my $c=pop @b;
+    if ($c->[-1] >= $terminal) {
+      $reward=max($reward,sum(map {$houses->[$_]} @{$c}));
+    } else {
+      foreach my $n ($c->[-1]+2..$c->[-1]+3) {
+        if ($n >= scalar @{$houses}) {
+          last;
+        }
+        push @b,[@{$c},$n];
+      }
+    }
+  }
+  return $reward;
+}
diff --git a/challenge-151/roger-bell-west/postscript/ch-1.ps b/challenge-151/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..85f11a949b
--- /dev/null
+++ b/challenge-151/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,90 @@
+%!PS
+
+/apush { % [a b] c -> [a b c]
+    /t exch def
+    [ exch aload pop t ]
+} bind def
+
+/strtok {
+    1 dict begin
+    /out 0 array def
+    {
+        ( ) search
+        {
+            out exch apush /out exch def
+            pop
+        } {
+            out exch apush /out exch def
+            exit
+        } ifelse
+    } loop
+    out
+    end
+} bind def
+
+/str2tree {
+    7 dict begin
+    /o [ 0 ] def
+    /d 0 def
+    /p 0 def
+    strtok {
+        dup (|) eq {
+            pop
+            /d d 1 add def
+            /p 0 def
+            /m 1 d 1 add bitshift 1 sub def
+            o length m lt {
+                m o length sub {
+                    /o o 0 apush def
+                } repeat
+            } if
+        } {
+            dup (*) eq {
+                pop
+                /y 0 def
+            } {
+                cvi /y exch def
+            } ifelse
+            o 1 d bitshift 1 sub p add y put
+            /p p 1 add def
+        } ifelse
+    } forall
+    o
+    end
+} bind def
+
+/mindepth {
+    5 dict begin
+    /tree exch def
+    tree length /firstleaf exch def
+    /i 0 def
+    0 1 tree length 1 sub {
+        0 ne {
+            i 1 add 1 bitshift tree length ge {
+                /firstleaf i def
+                exit
+            } {
+                /ni i 1 add 1 bitshift 1 sub def
+                tree ni get 0 eq tree ni 1 add get 0 eq and {
+                    /firstleaf i def
+                    exit
+                } if
+            } ifelse
+        } if
+        /i i 1 add def
+    } for
+    /t firstleaf 1 add def
+    /d 0 def
+    {
+        t 0 le {
+            exit
+        } if
+        /t t -1 bitshift def
+        /d d 1 add def
+    } loop
+    d
+    end
+} bind def
+
+(1 | 2 3 | 4 5) str2tree mindepth 2 eq { (Pass) } { (FAIL) } ifelse print ( ) print
+(1 | 2 3 | 4 * * 5 | * 6) str2tree mindepth 3 eq { (Pass) } { (FAIL) } ifelse =
diff --git a/challenge-151/roger-bell-west/postscript/ch-2.ps b/challenge-151/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..0791d79596
--- /dev/null
+++ b/challenge-151/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,52 @@
+%!PS
+
+/apush { % [a b] c -> [a b c]
+    1 dict begin
+    /t exch def
+    [ exch aload pop t ]
+    end
+} bind def
+
+/apop { % [a b c] -> [a b] c
+    1 dict begin
+    [ exch aload pop /t exch def ] t
+    end
+} bind def
+
+/plan {
+    8 dict begin
+    /houses exch def
+    /terminal houses length 2 sub def
+    /b [ [ 0 ] ] def
+    /reward 0 def
+    {
+        b length 0 le {
+            exit
+        } if
+        b apop /c exch def /b exch def
+        /c1 c c length 1 sub get def
+        c1 terminal ge {
+            /r 0 def
+            c {
+                houses exch get r add /r exch def
+            } forall
+            r reward gt {
+                /reward r def
+            } if
+        } {
+            c1 2 add 1 c1 3 add {
+                /n exch def
+                n houses length ge {
+                    exit
+                } if
+                b [ c aload pop n ] apush /b exch def
+            } for
+        } ifelse
+    } loop
+    reward
+    end
+} bind def
+
+[ 2 4 5 ] plan 7 eq { (Pass) } { (FAIL) } ifelse print ( ) print
+
+[ 4 2 3 6 5 3 ] plan 13 eq { (Pass) } { (FAIL) } ifelse =
diff --git a/challenge-151/roger-bell-west/python/ch-1.py b/challenge-151/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..34dff6a976
--- /dev/null
+++ b/challenge-151/roger-bell-west/python/ch-1.py
@@ -0,0 +1,54 @@
+#! /usr/bin/python3
+
+import unittest
+
+def str2tree(str):
+  o=[0]
+  d=0
+  p=0
+  for e in str.split():
+    if e == '|':
+      d += 1
+      p=0
+      m=(1<<(d+1))-1
+      while len(o) < m:
+        o.append(0)
+    else:
+      if e == '*':
+        y=0
+      else:
+        y=int(e)
+      i = (1<<d) - 1 + p
+      o[i]=y
+      p += 1
+  return o
+
+def mindepth(tree):
+  firstleaf=len(tree)
+  for i,e in enumerate(tree):
+    if e==0:
+      continue
+    elif (i+1) << 1 >= len(tree):
+      firstleaf=i
+      break
+    else:
+      ni=((i+1) << 1) -1
+      if tree[ni]==0 and tree[ni+1]==0:
+        firstleaf=i
+        break
+  t=firstleaf+1
+  d=0
+  while t > 0:
+    t >>= 1
+    d += 1
+  return d
+
+class TestStr2tree(unittest.TestCase):
+
+        def test_ex1(self):
+          self.assertEqual(mindepth(str2tree("1 | 2 3 | 4 5")),2,'example 1')
+
+        def test_ex2(self):
+          self.assertEqual(mindepth(str2tree("1 | 2 3 | 4 *  * 5 | * 6")),3,'example 2')
+
+unittest.main()
diff --git a/challenge-151/roger-bell-west/python/ch-2.py b/challenge-151/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..dec69ca6af
--- /dev/null
+++ b/challenge-151/roger-bell-west/python/ch-2.py
@@ -0,0 +1,32 @@
+#! /usr/bin/python3
+
+import unittest
+
+def plan(houses):
+  terminal=len(houses)-2
+  b=[[0]]
+  reward=0
+  while len(b) > 0:
+    c=b.pop()
+    if c[-1] >= terminal:
+      r=sum(houses[i] for i in c)
+      if r > reward:
+        reward=r
+    else:
+      for n in range(c[-1]+2,c[-1]+4):
+        if n >= len(houses):
+          break
+        j=c.copy()
+        j.append(n)
+        b.append(j)
+  return reward
+
+class TestPlan(unittest.TestCase):
+
+        def test_ex1(self):
+          self.assertEqual(plan([2, 4, 5]),7,'example 1')
+
+        def test_ex2(self):
+          self.assertEqual(plan([4, 2, 3, 6, 5, 3]),13,'example 2')
+
+unittest.main()
diff --git a/challenge-151/roger-bell-west/raku/ch-1.p6 b/challenge-151/roger-bell-west/raku/ch-1.p6
new file mode 100755
index 0000000000..0558352065
--- /dev/null
+++ b/challenge-151/roger-bell-west/raku/ch-1.p6
@@ -0,0 +1,58 @@
+#! /usr/bin/perl6
+
+use Test;
+plan 2;
+
+is(mindepth(str2tree("1 | 2 3 | 4 5")),2,'example 1');
+
+is(mindepth(str2tree("1 | 2 3 | 4 *  * 5 | * 6")),3,'example 2');
+
+sub str2tree($st) {
+    my @o;
+    my $d=0;
+    my $p=0;
+    for $st.words -> $e {
+        if ($e eq '|') {
+            $d++;
+            $p=0;
+            my $m=(1 +< ($d+1))-1;
+            if (@o.elems < $m) {
+                @o.append(0 x ($m - @o.elems));
+            }
+        } else {
+            my $y=0;
+            if ($e ne '*') {
+                $y=0+$e;
+            }
+            my $i=(1 +< $d) -1 +$p;
+            @o[$i]=$y;
+            $p++;
+        }
+    }
+    return @o;
+}
+
+sub mindepth(@tree) {
+    my $firstleaf=@tree.elems;
+    for @tree.kv -> $i,$e {
+        if ($e==0) {
+            next;
+        } elsif (($i+1) +< 1 >= @tree.elems) {
+            $firstleaf=$i;
+            last;
+        } else {
+            my $ni=(($i+1) +< 1)-1;
+            if (@tree[$ni]==0 && @tree[$ni+1]==0) {
+                $firstleaf=$i;
+                last;
+            }
+        }
+    }
+    my $t=$firstleaf+1;
+    my $d=0;
+    while ($t > 0) {
+        $t +>= 1;
+        $d++;
+    }
+    return $d;
+}
diff --git a/challenge-151/roger-bell-west/raku/ch-2.p6 b/challenge-151/roger-bell-west/raku/ch-2.p6
new file mode 100755
index 0000000000..59868af6d3
--- /dev/null
+++ b/challenge-151/roger-bell-west/raku/ch-2.p6
@@ -0,0 +1,31 @@
+#! /usr/bin/perl6
+
+use Test;
+
+plan 2;
+
+is(planloot([2, 4, 5]),7,'example 1');
+
+is(planloot([4, 2, 3, 6, 5, 3]),13,'example 2');
+
+sub planloot(@houses) {
+    my $terminal=@houses.elems-2;
+    my @b=[[0]];
+    my $reward=0;
+    while (@b.elems > 0) {
+        my @c=(pop @b).flat;
+        if (@c[*-1] >= $terminal) {
+            $reward=max($reward,sum(map {@houses[$_]}, @c));
+        } else {
+            for @c[*-1]+2..@c[*-1]+3 -> $n {
+                if ($n >= @houses.elems) {
+                    last;
+                }
+                my @j=@c.clone;
+                @j.append($n);
+                push @b,@j;
+            }
+        }
+    }
+    return $reward;
+}
diff --git a/challenge-151/roger-bell-west/ruby/ch-1.rb b/challenge-151/roger-bell-west/ruby/ch-1.rb
new file mode 100755
index 0000000000..902dc37fa6
--- /dev/null
+++ b/challenge-151/roger-bell-west/ruby/ch-1.rb
@@ -0,0 +1,65 @@
+#! /usr/bin/ruby
+
+require 'test/unit'
+
+def str2tree(st)
+  o=[]
+  d=0
+  p=0
+  st.split(' ').each do |e|
+    if e == "|" then
+      d += 1
+      p = 0
+      m = (1 << (d+1)) -1
+      while o.length < m do
+        o.push(0)
+      end
+    else
+      y=0
+      if e != "*" then
+        y=e.to_i
+      end
+      i = (1 << d) -1 +p
+      o[i] = y 
+      p += 1
+    end
+  end
+  return o
+end
+
+def mindepth(tree)
+  firstleaf=tree.length
+  tree.each_with_index do |e,i|
+    if e==0 then
+      next
+    elsif (i+1) << 1 >= tree.length then
+      firstleaf = i
+      break
+    else
+      ni=((i+1) << 1)-1
+      if tree[ni] == 0 && tree[ni+1] == 0 then
+        firstleaf=i
+        break
+      end
+    end
+  end
+  t=firstleaf+1
+  d=0
+  while t>0 do
+    t >>= 1
+    d += 1
+  end
+  return d
+end
+
+class TestMindepth < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(2,mindepth(str2tree("1 | 2 3 | 4 5")))
+  end
+
+  def test_ex2
+    assert_equal(3,mindepth(str2tree("1 | 2 3 | 4 *  * 5 | * 6")))
+  end
+
+end
diff --git a/challenge-151/roger-bell-west/ruby/ch-2.rb b/challenge-151/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..1d98a8824e
--- /dev/null
+++ b/challenge-151/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,37 @@
+#! /usr/bin/ruby
+
+require 'test/unit'
+
+def plan(houses)
+  terminal=houses.length-2
+  b=[[0]]
+  reward=0
+  while b.length > 0 do
+    c=b.pop
+    if c[-1] >= terminal then
+      reward=[reward,c.map{|i| houses[i]}.sum].max
+    else
+      (c[-1]+2).upto(c[-1]+3) do |n|
+        if n >= houses.length then
+          break
+        end
+        j=Array.new(c)
+        j.push(n)
+        b.push(j)
+      end
+    end
+  end
+  return reward
+end
+
+class TestPlan < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(7,plan([2, 4, 5]))
+  end
+
+  def test_ex2
+    assert_equal(13,plan([4, 2, 3, 6, 5, 3]))
+  end
+
+end
diff --git a/challenge-151/roger-bell-west/rust/ch-1.rs b/challenge-151/roger-bell-west/rust/ch-1.rs
new file mode 100755
index 0000000000..94afd0ebaf
--- /dev/null
+++ b/challenge-151/roger-bell-west/rust/ch-1.rs
@@ -0,0 +1,62 @@
+#! /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!(mindepth(str2tree("1 | 2 3 | 4 5")), 2);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(mindepth(str2tree("1 | 2 3 | 4 *  * 5 | * 6")), 3);
+}
+
+fn str2tree(st: &str) -> Vec<u32> {
+    let mut o: Vec<u32> = vec![0];
+    let mut d = 0;
+    let mut p = 0;
+    for e in st.split_whitespace() {
+        if e == "|" {
+            d += 1;
+            p = 0;
+            let m = (1 << (d + 1)) - 1;
+            if o.len() < m {
+                o.resize(m, 0);
+            }
+        } else {
+            let mut y = 0;
+            if e != "*" {
+                y = e.parse::<u32>().unwrap();
+            }
+            let i = (1 << d) - 1 + p;
+            o[i] = y;
+            p += 1;
+        }
+    }
+    return o;
+}
+
+fn mindepth(tree: Vec<u32>) -> usize {
+    let mut firstleaf = tree.len();
+    for (i, e) in tree.iter().enumerate() {
+        if *e == 0 {
+            continue;
+        } else if (i + 1) << 1 >= tree.len() {
+            firstleaf = i;
+            break;
+        } else {
+            let ni = ((i + 1) << 1) - 1;
+            if tree[ni] == 0 && tree[ni + 1] == 0 {
+                firstleaf = i;
+                break;
+            }
+        }
+    }
+    firstleaf += 1;
+    let mut d = 0;
+    while firstleaf > 0 {
+        firstleaf >>= 1;
+        d += 1;
+    }
+    return d;
+}
diff --git a/challenge-151/roger-bell-west/rust/ch-2.rs b/challenge-151/roger-bell-west/rust/ch-2.rs
new file mode 100755
index 0000000000..a8319fee65
--- /dev/null
+++ b/challenge-151/roger-bell-west/rust/ch-2.rs
@@ -0,0 +1,38 @@
+#! /bin/sh
+//usr/bin/env rustc --test $0 -o ${0}x && ./${0}x --nocapture; rm -f ${0}x ; exit
+
+#[test]
+fn test_ex1() {
+    assert_eq!(plan(vec![2, 4, 5]), 7);
+}
+
+#[test]
+fn test_ex2() {
+    assert_eq!(plan(vec![4, 2, 3, 6, 5, 3]), 13);
+}
+
+fn plan(houses: Vec<u32>) -> u32 {
+    let terminal = houses.len() - 2;
+    let mut b = vec![vec![0]];
+    let mut reward = 0;
+    while b.len() > 0 {
+        let c = b.pop().unwrap();
+        let c1 = c[c.len() - 1];
+        if c1 >= terminal {
+            let r = c.iter().map(|i| houses[*i]).sum();
+            if r > reward {
+                reward = r;
+            }
+        } else {
+            for n in (c1 + 2)..=(c1 + 3) {
+                if n >= houses.len() {
+                    break;
+                }
+                let mut j = c.clone();
+                j.push(n);
+                b.push(j);
+            }
+        }
+    }
+    return reward;
+}