1 files changed, 45 insertions, 0 deletions
diff --git a/challenge-082/roger-bell-west/ruby/ch-2.rb b/challenge-082/roger-bell-west/ruby/ch-2.rb
new file mode 100755
index 0000000000..067bddb305
--- /dev/null
+++ b/challenge-082/roger-bell-west/ruby/ch-2.rb
@@ -0,0 +1,45 @@
+#! /usr/bin/ruby
+
+def isinterleave(a,b,c)
+  l=[a,b,c].map{|x| x.length}
+  buf=[[0,0,0]]
+  while (!buf.empty?)
+    n=buf.pop
+    if (n[2] >= l[2])
+      return 1
+    end
+    if ((n[0] < l[0]) and (a[n[0]] == c[n[2]]))
+      buf.push([n[0]+1,n[1],n[2]+1])
+    end
+    if ((n[1] < l[1]) and (b[n[1]] == c[n[2]]))
+      buf.push([n[0],n[1]+1,n[2]+1])
+    end
+  end
+  return 0
+end
+
+require 'test/unit'
+
+class TestInterleave < Test::Unit::TestCase
+
+  def test_ex1
+    assert_equal(isinterleave('XY','X','XXY'),1)
+  end
+
+  def test_ex2
+    assert_equal(isinterleave('XXY','XXZ','XXXXZY'),1)
+  end
+
+  def test_ex3
+    assert_equal(isinterleave('YX','X','XXY'),0)
+  end
+
+  def test_ex4
+    assert_equal(isinterleave('ACF','BDEG','ABCDEFG'),1)
+  end
+
+  def test_ex5
+    assert_equal(isinterleave('ACF','BDGE','ABCDEFG'),0)
+  end
+
+end