yemou.pink
+1
2015/05/part1-tests/expected
+1
2015/05/part1-tests/expected
···
1
+
2
+5
2015/05/part1-tests/input1
+5
2015/05/part1-tests/input1
+1
2015/05/part2-tests/expected
+1
2015/05/part2-tests/expected
···
1
+
2
+4
2015/05/part2-tests/input1
+4
2015/05/part2-tests/input1
+113
2015/05/solution.erl
+113
2015/05/solution.erl
···
1
+
#!/usr/bin/env escript
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+
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+
% --- Part 1 Code
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part1(Input) ->
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io:format("Part 1: ~b~n", [count_nice_strings(Input, 0)]).
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+
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count_vowels(String) ->
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lists:foldl(
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fun(Char, Total) ->
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case lists:member(Char, "aeiou") of
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true -> Total + 1;
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false -> Total
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end
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end,
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0,
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String
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).
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+
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has_consecutive_characters([_ | []]) ->
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false;
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has_consecutive_characters(String) ->
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[First, Second | Rest] = String,
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case First == Second of
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true -> true;
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false -> has_consecutive_characters([Second] ++ Rest)
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end.
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+
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has_forbidden_pattern(String, Pattern) ->
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case string:find(String, Pattern) of
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nomatch -> false;
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_ -> true
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end.
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+
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is_nice_string(String) ->
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maybe
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true ?= count_vowels(String) >= 3,
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true ?= has_consecutive_characters(String),
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true ?= has_forbidden_pattern(String, "ab") == false,
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true ?= has_forbidden_pattern(String, "cd") == false,
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true ?= has_forbidden_pattern(String, "pq") == false,
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true ?= has_forbidden_pattern(String, "xy") == false
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end.
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+
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count_nice_strings([], Total) ->
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Total;
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count_nice_strings([Head | Rest], Total) ->
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case is_nice_string(Head) of
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true -> count_nice_strings(Rest, Total + 1);
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false -> count_nice_strings(Rest, Total)
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end.
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+
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+
% --- Part 2 Code
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part2(Input) ->
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io:format("Part 2: ~b~n", [count_nice_strings2(Input, 0)]).
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+
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has_pattern(String, Pattern) ->
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case string:find(String, Pattern) of
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nomatch -> false;
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_ -> true
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end.
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+
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+
has_duplicate_pattern([_ | []]) ->
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false;
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has_duplicate_pattern(String) ->
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[First, Second | Rest] = String,
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case has_pattern(Rest, [First, Second]) of
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true -> true;
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false -> has_duplicate_pattern([Second] ++ Rest)
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end.
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+
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has_repeating_with_interrupt([_, _ | []]) ->
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false;
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+
has_repeating_with_interrupt(String) ->
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+
[Start, Middle, End | Rest] = String,
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+
case Start == End of
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true -> true;
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false -> has_repeating_with_interrupt([Middle, End] ++ Rest)
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end.
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+
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is_nice_string2(String) ->
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maybe
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true ?= has_duplicate_pattern(String),
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true ?= has_repeating_with_interrupt(String)
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end.
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+
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count_nice_strings2([], Total) ->
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Total;
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count_nice_strings2([Head | Rest], Total) ->
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case is_nice_string2(Head) of
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true -> count_nice_strings2(Rest, Total + 1);
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false -> count_nice_strings2(Rest, Total)
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end.
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+
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% --- Generic Helper Functions
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read_input() -> read_input("").
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read_input(PrevLine) ->
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case io:fread("", "~s") of
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eof -> PrevLine;
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{error, _} -> halt(1);
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{ok, Terms} -> read_input(PrevLine ++ Terms)
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end.
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+
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main(Args) ->
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Input = read_input(),
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case Args of
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["1"] ->
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+
part1(Input);
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+
["2"] ->
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+
part2(Input);
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+
_ ->
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+
part1(Input),
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+
part2(Input)
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+
end.