Initial data commit

Task/Semordnilap/Erlang/semordnilap.erl

@@ -0,0 +1,35 @@
+#!/usr/bin/env escript
+main([]) -> main(["unixdict.txt"]);
+
+main([DictFile]) ->
+  Dict = sets:from_list(read_lines(DictFile)),
+  Semordnilaps =
+    lists:filter(fun([W,R]) -> W < R end,
+      lists:map(fun(W) -> [W, lists:reverse(W)] end,
+        semordnilaps(Dict))),
+  io:fwrite("There are ~b semordnilaps in ~s~n",
+            [length(Semordnilaps), DictFile]),
+  lists:map(fun([W,R]) -> io:fwrite("~s/~s~n", [W, R]) end,
+            lists:sort(lists:sublist(shuffle(Semordnilaps),1,5))).
+
+read_lines(Filename) when is_list(Filename) ->
+  { ok, File } = file:open(Filename, [read]),
+  read_lines(File);
+
+read_lines(File) when is_pid(File) ->
+   case file:read_line(File) of
+    {ok, Data} -> [chop(Data) | read_lines(File)];
+    eof        -> []
+   end.
+
+is_semordnilap(Word, Dict) ->
+  Rev = lists:reverse(Word),
+  sets:is_element(Word, Dict) and sets:is_element(Rev, Dict).
+
+semordnilaps(Dict) ->
+  lists:filter(fun(W) -> is_semordnilap(W, Dict) end, sets:to_list(Dict)).
+
+shuffle(List) ->
+  [X||{_,X} <- lists:sort([ {random:uniform(), N} || N <- List])].
+
+chop(L) -> [_|T] = lists:reverse(L), lists:reverse(T).