Sync

Task/Semordnilap/Icon/semordnilap.icon

@@ -0,0 +1,11 @@
+procedure main(a)
+    words := set()
+    found := 0
+    every word := map(!&input) do {
+        if member(words, reverse(word)) then {
+            if (found +:= 1) <= 5 then write("\t",reverse(word),"/",word)
+            }
+        else insert(words, word)
+        }
+    write("\nFound ",found," semordnilap words")
+end

Task/Semordnilap/Lua/semordnilap.lua

@@ -0,0 +1,34 @@
+#!/usr/bin/env lua
+-- allow dictionary file and sample size to be specified on command line
+local dictfile = arg[1] or "unixdict.txt"
+local sample_size = arg[2] or 5;
+
+-- read dictionary
+local f = assert(io.open(dictfile, "r"))
+local dict = {}
+for line in f:lines() do
+  dict[line] = line:reverse()
+end
+f:close()
+
+-- find the semordnilaps
+local semordnilaps = {}
+for fwd, rev in pairs(dict) do
+  if dict[rev] and fwd < rev then
+    table.insert(semordnilaps, {fwd,rev})
+  end
+end
+
+-- print the report
+print("There are " .. #semordnilaps .. " semordnilaps in " .. dictfile .. ".  Here are " .. sample_size .. ":")
+
+math.randomseed( os.time() )
+for i = 1, sample_size do
+  local j
+  repeat
+    j = math.random(1,#semordnilaps)
+  until semordnilaps[j]
+  local f, r = unpack(semordnilaps[j])
+  semordnilaps[j] = nil
+  print(f .. " -> " .. r)
+end