AdventOfCode/2017/02/2.md

## \-\-- 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?

Your puzzle answer was `34925`.

## \-\-- Part Two \-\-- {#part2}

\"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]{title="Bonus points if you solve this part using only 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?

Your puzzle answer was `221`.

Both parts of this puzzle are complete! They provide two gold stars:
\*\*

At this point, you should [return to your Advent calendar](/2017) and
try another puzzle.

If you still want to see it, you can [get your puzzle
input](2/input).