Ch85 (Lua): Task 2

2 files changed, 31 insertions, 0 deletions

diff --git a/challenge-085/tyler-wardhaugh/lua/ch-2.lua b/challenge-085/tyler-wardhaugh/lua/ch-2.lua
new file mode 100755
index 0000000000..6af287ab8d
--- /dev/null
+++ b/challenge-085/tyler-wardhaugh/lua/ch-2.lua
@@ -0,0 +1,22 @@
+#!/usr/bin/env lua
+
+local t2 = {}
+
+function t2.has_power_expr(n)
+  local endpoint = function(x) return 1 + math.floor(math.log(n, x)) end
+  for a = 2,endpoint(2) do
+    for b = 2,endpoint(a) do
+      if n == a ^ b then
+        return 1
+      end
+    end
+  end
+
+  return 0
+end
+
+function t2.run(args)
+  print(t2.has_power_expr(tonumber(args[1])))
+end
+
+return t2
diff --git a/challenge-085/tyler-wardhaugh/lua/test.lua b/challenge-085/tyler-wardhaugh/lua/test.lua
index 4577757e03..fdac1e33d8 100755
--- a/challenge-085/tyler-wardhaugh/lua/test.lua
+++ b/challenge-085/tyler-wardhaugh/lua/test.lua
@@ -18,3 +18,12 @@ describe("Task 1, Triplet Sum", function()
     assert.are.same(1, t1.find_triplet_sum(big))
   end)
 end)
+
+describe("Task 2, Power of Two Integers", function()
+  local t2 = require'ch-2'
+  it("produces correct results for the examples", function()
+    assert.are.same(1, t2.has_power_expr(8))
+    assert.are.same(0, t2.has_power_expr(15))
+    assert.are.same(1, t2.has_power_expr(125))
+  end)
+end)