Merge branch 'master' of https://github.com/manwar/perlweeklychallenge-club

1 files changed, 49 insertions, 0 deletions

diff --git a/challenge-113/stuart-little/lua/ch-2.lua b/challenge-113/stuart-little/lua/ch-2.lua
new file mode 100755
index 0000000000..6a4f64e368
--- /dev/null
+++ b/challenge-113/stuart-little/lua/ch-2.lua
@@ -0,0 +1,49 @@
+#!/usr/bin/env lua
+
+require 'luarocks.loader'
+local inspect = require 'inspect'
+
+sm=0
+for _,v in ipairs(arg) do
+   if v ~= "." then sm=sm+v end
+end
+for k,v in ipairs(arg) do
+   if v ~= "." then arg[k]=("%d"):format(sm-v) end
+end
+
+function oneOver(t)
+   local count=0
+   for k,v in ipairs(t) do
+      count = count + (v == "." and 1 or -1)
+      if count == 1 then return k end
+   end
+end
+
+function strs2t(lst)
+   if lst[1] == "." then return end
+   local val=table.remove(lst,1)
+   local ix=oneOver(lst)
+   local llst = {table.unpack(lst,1,ix)}
+   local rlst = {table.unpack(lst,ix+1)}
+   return {{val},l=strs2t(llst),r=strs2t(rlst)}
+end
+
+print(inspect(strs2t(arg)))
+
+--[[
+run <script> <tree in preorder form with '.' for empty nodes, entered as space-separated values>
+
+ref: https://stackoverflow.com/a/2676849/11064961
+
+e.g. 1 2 4 . 7 . . . 3 5 . . 6 . . represents the tree
+
+        1
+       / \
+      2   3
+     /   / \
+    4   5   6
+     \
+      7
+
+given as an example in the problem formulation at https://perlweeklychallenge.org/blog/perl-weekly-challenge-113/#TASK2
+--]]