Merge pull request #2422 from tylerw/tw/challenge-080-lua

Ch80: add Lua solutions

5 files changed, 94 insertions, 4 deletions

diff --git a/challenge-080/tyler-wardhaugh/lua/README.md b/challenge-080/tyler-wardhaugh/lua/README.md
index db3ed46069..c469977934 100644
--- a/challenge-080/tyler-wardhaugh/lua/README.md
+++ b/challenge-080/tyler-wardhaugh/lua/README.md
@@ -7,15 +7,15 @@ The Weekly Challenge - #080 - Tyler Wardhaugh
 
 Run Task 1:
 
-    $
+    $ ./run.lua ch-1 5 2 -2 0
 
 Run Task 2:
 
-    $
+    $ ./run.lua ch-2 1 2 2
 
-Run the project's tests (which are samples from the task descriptions):
+Run the project's tests (all the samples from the task descriptions plus some others):
 
-    $ lua test.lua
+    $ ./test.lua
 
 ## Requirements:
 *   [Lua](https://www.lua.org/) 5.3
diff --git a/challenge-080/tyler-wardhaugh/lua/ch-1.lua b/challenge-080/tyler-wardhaugh/lua/ch-1.lua
new file mode 100755
index 0000000000..aa54879fac
--- /dev/null
+++ b/challenge-080/tyler-wardhaugh/lua/ch-1.lua
@@ -0,0 +1,33 @@
+#!/usr/bin/env lua
+
+local t1 = {}
+
+function t1.smallest_missing(coll)
+  local range = {0}
+  for _, v in ipairs(coll) do
+    if v > 0 then table.insert(range, v) end
+  end
+  table.sort(range)
+
+  local next, cur
+  for i=1,#range do
+    cur = range[i]
+    next = range[i+1]
+
+    if next and ((next - cur) > 1) then
+      return cur + 1
+    end
+  end
+
+  -- there are no gaps, therefore the smallest "missing" positive integer is
+  -- the maximum number given (i.e., the last one in the sorted table) plus one
+  return range[#range] + 1
+end
+
+function t1.run(arg)
+  local N = {}
+  for _, v in ipairs(arg) do table.insert(N, tonumber(v)) end
+  print(t1.smallest_missing(N))
+end
+
+return t1
diff --git a/challenge-080/tyler-wardhaugh/lua/ch-2.lua b/challenge-080/tyler-wardhaugh/lua/ch-2.lua
new file mode 100755
index 0000000000..54d355d037
--- /dev/null
+++ b/challenge-080/tyler-wardhaugh/lua/ch-2.lua
@@ -0,0 +1,25 @@
+#!/usr/bin/env lua
+
+local t2 = {}
+
+function t2.count_candies(coll)
+  local count = #coll
+  local maybe_inc = function(i, j)
+    if (coll[i] > coll[j]) then count = count + 1 end
+  end
+
+  -- sweep left-to-right
+  for i=1,#coll-1 do maybe_inc(i, i+1) end
+  -- sweep right-to-left
+  for i=#coll,2,-1 do maybe_inc(i, i-1) end
+
+  return count
+end
+
+function t2.run(arg)
+  local N = {}
+  for _, v in ipairs(arg) do table.insert(N, tonumber(v)) end
+  print(t2.count_candies(N))
+end
+
+return t2
diff --git a/challenge-080/tyler-wardhaugh/lua/run.lua b/challenge-080/tyler-wardhaugh/lua/run.lua
new file mode 100755
index 0000000000..c6e7473bee
--- /dev/null
+++ b/challenge-080/tyler-wardhaugh/lua/run.lua
@@ -0,0 +1,9 @@
+#!/usr/bin/env lua
+
+local filename = arg[1]
+local run_args = table.move(arg, 2, #arg, 1, {})
+
+io.write(string.format("Running task from '%s' with {%s}:\n",
+  filename, table.concat(run_args, ", ")))
+
+require(filename).run(run_args)
diff --git a/challenge-080/tyler-wardhaugh/lua/test.lua b/challenge-080/tyler-wardhaugh/lua/test.lua
new file mode 100755
index 0000000000..44d03f8844
--- /dev/null
+++ b/challenge-080/tyler-wardhaugh/lua/test.lua
@@ -0,0 +1,23 @@
+#!/usr/bin/env lua
+
+require 'busted.runner'()
+
+describe("Task 1, Smallest Positive Number", function()
+  local t1 = require'ch-1'
+  it("produces correct results for the examples", function()
+    assert.are.same(t1.smallest_missing({5, 2, -2, 0}), 1)
+    assert.are.same(t1.smallest_missing({1, 8, -1}), 2)
+    assert.are.same(t1.smallest_missing({2, 0, -1}), 1)
+    assert.are.same(t1.smallest_missing({-5, -4, -3}), 1)
+    assert.are.same(t1.smallest_missing({1, 2, 3, 10000000}), 4)
+    assert.are.same(t1.smallest_missing({1, 4, 2, 3}), 5)
+  end)
+end)
+
+describe("Task 2, Count Candies", function()
+  local t2  = require'ch-2'
+  it("produces correct results for the examples", function()
+    assert.are.same(t2.count_candies({1, 2, 2}), 4)
+    assert.are.same(t2.count_candies({1, 4, 3, 2}), 7)
+  end)
+end)