60 lines
2.2 KiB
Markdown
60 lines
2.2 KiB
Markdown
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## \-\-- Day 1: Not Quite Lisp \-\--
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Santa was hoping for a white Christmas, but his weather machine\'s
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\"snow\" function is powered by stars, and he\'s fresh out! To save
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Christmas, he needs you to collect *fifty stars* by December 25th.
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Collect stars by helping Santa solve puzzles. Two puzzles will be made
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available on each day in the Advent calendar; the second puzzle is
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unlocked when you complete the first. Each puzzle grants *one star*.
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[Good
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luck!]{title="Also, some puzzles contain Easter eggs like this one. Yes, I know it's not traditional to do Advent calendars for Easter."}
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Here\'s an easy puzzle to warm you up.
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Santa is trying to deliver presents in a large apartment building, but
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he can\'t find the right floor - the directions he got are a little
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confusing. He starts on the ground floor (floor `0`) and then follows
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the instructions one character at a time.
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An opening parenthesis, `(`, means he should go up one floor, and a
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closing parenthesis, `)`, means he should go down one floor.
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The apartment building is very tall, and the basement is very deep; he
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will never find the top or bottom floors.
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For example:
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- `(())` and `()()` both result in floor `0`.
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- `(((` and `(()(()(` both result in floor `3`.
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- `))(((((` also results in floor `3`.
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- `())` and `))(` both result in floor `-1` (the first basement
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level).
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- `)))` and `)())())` both result in floor `-3`.
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To *what floor* do the instructions take Santa?
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## \-\-- Part Two \-\-- {#part2}
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Now, given the same instructions, find the *position* of the first
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character that causes him to enter the basement (floor `-1`). The first
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character in the instructions has position `1`, the second character has
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position `2`, and so on.
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For example:
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- `)` causes him to enter the basement at character position `1`.
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- `()())` causes him to enter the basement at character position `5`.
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What is the *position* of the character that causes Santa to first enter
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the basement?
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Both parts of this puzzle are complete! They provide two gold stars:
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\*\*
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At this point, you should [return to your Advent calendar](/2015) and
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try another puzzle.
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If you still want to see it, you can [get your puzzle
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input](1/input).
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