Merge pull request #4517 from stuart-little/stuart-little_079_lua

1st commit on 079_lua

2 files changed, 48 insertions, 0 deletions

diff --git a/challenge-079/stuart-little/lua/ch-1.lua b/challenge-079/stuart-little/lua/ch-1.lua
new file mode 100755
index 0000000000..ed17d5faac
--- /dev/null
+++ b/challenge-079/stuart-little/lua/ch-1.lua
@@ -0,0 +1,13 @@
+#!/usr/bin/env lua
+
+-- run <script> <number>
+-- https://oeis.org/A000788
+
+function bitsUpTo(n)
+   if n <= 1 then return n end
+   local topBitPos = math.floor(math.log(n,2))
+   local rest = n ~ 2^topBitPos
+   return 1+topBitPos*2^(topBitPos-1) + rest + bitsUpTo(rest)
+end
+
+print(("%d"):format(bitsUpTo(tonumber(arg[1]))))
diff --git a/challenge-079/stuart-little/lua/ch-2.lua b/challenge-079/stuart-little/lua/ch-2.lua
new file mode 100755
index 0000000000..23247611bd
--- /dev/null
+++ b/challenge-079/stuart-little/lua/ch-2.lua
@@ -0,0 +1,35 @@
+#!/usr/bin/env lua
+
+-- run <script> <space-separated numbers>
+
+function histo(t)
+   local mx = math.max(table.unpack(t))
+   local h={}
+   for i=0,mx-1 do
+      local row={}
+      for k,v in ipairs(t) do
+	 table.insert(row,v < mx-i and " " or "#")
+      end
+      table.insert(h,row)
+   end
+   return h
+end
+
+function rain(t)
+   local q=0
+   for k,v in ipairs(t) do
+      if k > 1 and k < #t then
+	 local l = math.max(table.unpack(t,1,k-1))
+	 local r = math.max(table.unpack(t,k+1))
+	 local m = math.min(l,r)
+	 q=q+math.max(0,m-v)
+      end
+   end
+   return q
+end
+
+local nums={}
+for _,nr in ipairs(arg) do table.insert(nums,tonumber(nr)) end
+for _,row in ipairs(histo(nums)) do print(table.unpack(row)) end
+print(("-"):rep(20))
+print(rain(nums))