Given a word and a list of possible anagrams, select the correct sublist.
Given "listen"
and a list of candidates like "enlists" "google" "inlets" "banana"
the program should return a list containing
"inlets"
.
Execute the tests with:
$ mix test
In the test suites, all but the first test have been skipped.
Once you get a test passing, you can unskip the next one by
commenting out the relevant @tag :pending
with a #
symbol.
For example:
# @tag :pending
test "shouting" do
assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
end
Or, you can enable all the tests by commenting out the
ExUnit.configure
line in the test suite.
# ExUnit.configure exclude: :pending, trace: true
If you're stuck on something, it may help to look at some of the available resources out there where answers might be found.
Inspired by the Extreme Startup game https://github.com/rchatley/extreme_startup
It's possible to submit an incomplete solution so you can see how others have completed the exercise.
defmodule AnagramTest do
use ExUnit.Case
# @tag :pending
test "no matches" do
matches = Anagram.match("diaper", ~w(hello world zombies pants))
assert matches == []
end
@tag :pending
test "detects two anagrams" do
matches = Anagram.match("master", ~w(stream pigeon maters))
assert matches == ~w(stream maters)
end
@tag :pending
test "does not detect anagram subsets" do
matches = Anagram.match("good", ~w(dog goody))
assert matches == []
end
@tag :pending
test "detects anagram" do
matches = Anagram.match("listen", ~w(enlists google inlets banana))
assert matches == ~w(inlets)
end
@tag :pending
test "detects three anagrams" do
matches = Anagram.match("allergy", ~w(gallery ballerina regally clergy largely leading))
assert matches == ~w(gallery regally largely)
end
@tag :pending
test "detects multiple anagrams with different case" do
matches = Anagram.match("nose", ~w(Eons ONES))
assert matches == ~w(Eons ONES)
end
@tag :pending
test "does not detect non-anagrams with identical checksum" do
matches = Anagram.match("mass", ~w(last))
assert matches == []
end
@tag :pending
test "detect anagramss case-insensitively" do
matches = Anagram.match("orchestra", ~w(cashregister Carthorse radishes))
assert matches == ~w(Carthorse)
end
@tag :pending
test "detects anagrams using case-insensitive subject" do
matches = Anagram.match("Orchestra", ~w(cashregister carthorse radishes))
assert matches == ~w(carthorse)
end
@tag :pending
test "detects anagrams using case-insensitive possible matches" do
matches = Anagram.match("orchestra", ~w(cashregister Carthorse radishes))
assert matches == ~w(Carthorse)
end
@tag :pending
test "does not detect an anagram if the original word is repeated" do
matches = Anagram.match("go", ~w(go Go GO))
assert matches == []
end
@tag :pending
test "anagrams must use all letters exactly once" do
matches = Anagram.match("tapper", ~w(patter))
assert matches == []
end
@tag :pending
test "words are not anagrams of themselves (case-insensitive)" do
matches = Anagram.match("BANANA", ~w(BANANA Banana banana))
assert matches == []
end
@tag :pending
test "words other than themselves can be anagrams" do
matches = Anagram.match("LISTEN", ~w(Listen Silent LISTEN))
assert matches == ~w(Silent)
end
end
ExUnit.start()
ExUnit.configure(exclude: :pending, trace: true)
defmodule Anagram do
@doc """
Returns all candidates that are anagrams of, but not equal to, 'base'.
"""
@spec match(String.t(), [String.t()]) :: [String.t()]
def match(base, candidates) do
Enum.filter(candidates, fn candidate ->
anagram?(String.downcase(base), String.downcase(candidate))
end)
end
defp anagram?(base, base), do: false
defp anagram?(base, candidate) do
sort_letters(base) == sort_letters(candidate)
end
defp sort_letters(string) do
string
|> String.split("")
|> Enum.sort()
end
end
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