2017-12-02 05:34:33 +00:00
|
|
|
|
Advent of Code
|
|
|
|
|
|
|
|
|
|
|
|
--- Day 2: Corruption Checksum ---
|
|
|
|
|
|
|
|
|
|
|
|
As you walk through the door, a glowing humanoid shape yells in your
|
|
|
|
|
|
direction. "You there! Your state appears to be idle. Come help us repair the
|
|
|
|
|
|
corruption in this spreadsheet - if we take another millisecond, we'll have
|
|
|
|
|
|
to display an hourglass cursor!"
|
|
|
|
|
|
|
|
|
|
|
|
The spreadsheet consists of rows of apparently-random numbers. To make sure
|
|
|
|
|
|
the recovery process is on the right track, they need you to calculate the
|
|
|
|
|
|
spreadsheet's checksum. For each row, determine the difference between the
|
|
|
|
|
|
largest value and the smallest value; the checksum is the sum of all of these
|
|
|
|
|
|
differences.
|
|
|
|
|
|
|
|
|
|
|
|
For example, given the following spreadsheet:
|
|
|
|
|
|
|
|
|
|
|
|
5 1 9 5
|
|
|
|
|
|
7 5 3
|
|
|
|
|
|
2 4 6 8
|
|
|
|
|
|
|
|
|
|
|
|
* The first row's largest and smallest values are 9 and 1, and their
|
|
|
|
|
|
difference is 8.
|
|
|
|
|
|
* The second row's largest and smallest values are 7 and 3, and their
|
|
|
|
|
|
difference is 4.
|
|
|
|
|
|
* The third row's difference is 6.
|
|
|
|
|
|
|
|
|
|
|
|
In this example, the spreadsheet's checksum would be 8 + 4 + 6 = 18.
|
|
|
|
|
|
|
|
|
|
|
|
What is the checksum for the spreadsheet in your puzzle input?
|
|
|
|
|
|
|
2018-03-15 15:08:01 +00:00
|
|
|
|
Your puzzle answer was 46402.
|
2017-12-02 05:34:33 +00:00
|
|
|
|
|
|
|
|
|
|
The first half of this puzzle is complete! It provides one gold star: *
|
|
|
|
|
|
|
|
|
|
|
|
--- Part Two ---
|
|
|
|
|
|
|
|
|
|
|
|
"Great work; looks like we're on the right track after all. Here's a star for
|
|
|
|
|
|
your effort." However, the program seems a little worried. Can programs be
|
|
|
|
|
|
worried?
|
|
|
|
|
|
|
|
|
|
|
|
"Based on what we're seeing, it looks like all the User wanted is some
|
|
|
|
|
|
information about the evenly divisible values in the spreadsheet.
|
|
|
|
|
|
Unfortunately, none of us are equipped for that kind of calculation - most of
|
|
|
|
|
|
us specialize in bitwise operations."
|
|
|
|
|
|
|
|
|
|
|
|
It sounds like the goal is to find the only two numbers in each row where one
|
|
|
|
|
|
evenly divides the other - that is, where the result of the division
|
|
|
|
|
|
operation is a whole number. They would like you to find those numbers on
|
|
|
|
|
|
each line, divide them, and add up each line's result.
|
|
|
|
|
|
|
|
|
|
|
|
For example, given the following spreadsheet:
|
|
|
|
|
|
|
|
|
|
|
|
5 9 2 8
|
|
|
|
|
|
9 4 7 3
|
|
|
|
|
|
3 8 6 5
|
|
|
|
|
|
|
|
|
|
|
|
* In the first row, the only two numbers that evenly divide are 8 and 2;
|
|
|
|
|
|
the result of this division is 4.
|
|
|
|
|
|
* In the second row, the two numbers are 9 and 3; the result is 3.
|
|
|
|
|
|
* In the third row, the result is 2.
|
|
|
|
|
|
|
|
|
|
|
|
In this example, the sum of the results would be 4 + 3 + 2 = 9.
|
|
|
|
|
|
|
|
|
|
|
|
What is the sum of each row's result in your puzzle input?
|
|
|
|
|
|
|
|
|
|
|
|
Although it hasn't changed, you can still get your puzzle input.
|
|
|
|
|
|
|
2018-03-15 15:08:01 +00:00
|
|
|
|
Answer: 265
|
2017-12-02 05:34:33 +00:00
|
|
|
|
|
|
|
|
|
|
References
|
|
|
|
|
|
|
|
|
|
|
|
Visible links
|
|
|
|
|
|
. http://adventofcode.com/
|
|
|
|
|
|
. http://adventofcode.com/2017/about
|
|
|
|
|
|
. http://adventofcode.com/2017/support
|
|
|
|
|
|
. http://adventofcode.com/2017/events
|
|
|
|
|
|
. http://adventofcode.com/2017/settings
|
|
|
|
|
|
. http://adventofcode.com/2017/auth/logout
|
|
|
|
|
|
. http://adventofcode.com/2017
|
|
|
|
|
|
. http://adventofcode.com/2017
|
|
|
|
|
|
. http://adventofcode.com/2017/leaderboard
|
|
|
|
|
|
. http://adventofcode.com/2017/stats
|
|
|
|
|
|
. http://adventofcode.com/2017/sponsors
|
|
|
|
|
|
. http://adventofcode.com/2017/sponsors
|
|
|
|
|
|
. http://adventofcode.com/2017/day/2/input
|
