1 files changed, 86 insertions, 0 deletions
diff --git a/challenge-213/roger-bell-west/lua/ch-2.lua b/challenge-213/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..a2d353c669
--- /dev/null
+++ b/challenge-213/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,86 @@
+#! /usr/bin/lua
+
+-- by Michael Anderson at
+-- https://stackoverflow.com/questions/8722620/comparing-two-index-tables-by-index-value-in-lua
+function recursive_compare(t1,t2)
+   if t1==t2 then return true end
+   if (type(t1)~="table") then return false end
+   local mt1 = getmetatable(t1)
+   local mt2 = getmetatable(t2)
+   if( not recursive_compare(mt1,mt2) ) then return false end
+   for k1,v1 in pairs(t1) do
+      local v2 = t2[k1]
+      if( not recursive_compare(v1,v2) ) then return false end
+   end
+   for k2,v2 in pairs(t2) do
+      local v1 = t1[k2]
+      if( not recursive_compare(v1,v2) ) then return false end
+   end
+   return true
+end
+
+function shortestroute(r0, origin, destination)
+   local r = {}
+   for _dummy, rt in ipairs(r0) do
+      for i = 1, #rt-1 do
+         local ri = rt[i]
+         local rj = rt[i + 1]
+         if r[ri] == nil then
+            r[ri] = {}
+         end
+         r[ri][rj] = true
+         if r[rj] == nil then
+            r[rj] = {}
+         end
+         r[rj][ri] = true
+      end
+   end
+   local out = {}
+   local stack = { { origin } }
+   while #stack > 0 do
+      local s = table.remove(stack, 1)
+      local l = s[#s]
+      if l == destination then
+         out = s
+         break
+      else
+         local s1 = {}
+         for _dummy, v in ipairs(s) do
+            s1[v] = true
+            end
+         for pd, _dummy in pairs(r[l]) do
+            if s1[pd] == nil then
+               local q = {}
+               for _dummy, v in ipairs(s) do
+                  table.insert(q, v)
+               end
+               table.insert(q, pd)
+               table.insert(stack, q)
+            end
+         end
+      end
+   end
+   return out
+end
+
+if recursive_compare(shortestroute({{1, 2, 6}, {5, 6, 7}}, 1, 7), {1, 2, 6, 7}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(shortestroute({{1, 2, 3}, {4, 5, 6}}, 2, 5), {}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if recursive_compare(shortestroute({{1, 2, 3}, {4, 5, 6}, {3, 8, 9}, {7, 8}}, 1, 7), {1, 2, 3, 8, 7}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+