64 lines
2.2 KiB
Markdown
64 lines
2.2 KiB
Markdown
|
## \-\-- Day 1: Not Quite Lisp \-\--
|
||
|
|
|
||
|
|
Santa was hoping for a white Christmas, but his weather machine\'s
|
||
|
|
\"snow\" function is powered by stars, and he\'s fresh out! To save
|
||
|
|
Christmas, he needs you to collect *fifty stars* by December 25th.
|
||
|
|
|
||
|
|
Collect stars by helping Santa solve puzzles. Two puzzles will be made
|
||
|
|
available on each day in the Advent calendar; the second puzzle is
|
||
|
|
unlocked when you complete the first. Each puzzle grants *one star*.
|
||
|
|
[Good
|
||
|
|
luck!]{title="Also, some puzzles contain Easter eggs like this one. Yes, I know it's not traditional to do Advent calendars for Easter."}
|
||
|
|
|
||
|
|
Here\'s an easy puzzle to warm you up.
|
||
|
|
|
||
|
|
Santa is trying to deliver presents in a large apartment building, but
|
||
|
|
he can\'t find the right floor - the directions he got are a little
|
||
|
|
confusing. He starts on the ground floor (floor `0`) and then follows
|
||
|
|
the instructions one character at a time.
|
||
|
|
|
||
|
|
An opening parenthesis, `(`, means he should go up one floor, and a
|
||
|
|
closing parenthesis, `)`, means he should go down one floor.
|
||
|
|
|
||
|
|
The apartment building is very tall, and the basement is very deep; he
|
||
|
|
will never find the top or bottom floors.
|
||
|
|
|
||
|
|
For example:
|
||
|
|
|
||
|
|
- `(())` and `()()` both result in floor `0`.
|
||
|
|
- `(((` and `(()(()(` both result in floor `3`.
|
||
|
|
- `))(((((` also results in floor `3`.
|
||
|
|
- `())` and `))(` both result in floor `-1` (the first basement
|
||
|
|
level).
|
||
|
|
- `)))` and `)())())` both result in floor `-3`.
|
||
|
|
|
||
|
|
To *what floor* do the instructions take Santa?
|
||
|
|
|
||
|
|
Your puzzle answer was `232`.
|
||
|
|
|
||
|
|
## \-\-- Part Two \-\-- {#part2}
|
||
|
|
|
||
|
|
Now, given the same instructions, find the *position* of the first
|
||
|
|
character that causes him to enter the basement (floor `-1`). The first
|
||
|
|
character in the instructions has position `1`, the second character has
|
||
|
|
position `2`, and so on.
|
||
|
|
|
||
|
|
For example:
|
||
|
|
|
||
|
|
- `)` causes him to enter the basement at character position `1`.
|
||
|
|
- `()())` causes him to enter the basement at character position `5`.
|
||
|
|
|
||
|
|
What is the *position* of the character that causes Santa to first enter
|
||
|
|
the basement?
|
||
|
|
|
||
|
|
Your puzzle answer was `1783`.
|
||
|
|
|
||
|
|
Both parts of this puzzle are complete! They provide two gold stars:
|
||
|
|
\*\*
|
||
|
|
|
||
|
|
At this point, you should [return to your Advent calendar](/2015) and
|
||
|
|
try another puzzle.
|
||
|
|
|
||
|
|
If you still want to see it, you can [get your puzzle
|
||
|
|
input](1/input).
|