Day 2 - njmnbb/Advent-of-Code GitHub Wiki

##Day 2 - I Was Told There Would Be No Math

The elves are running low on wrapping paper, and so they need to submit an order for more. They have a list of the dimensions (length l, width w, and height h) of each present, and only want to order exactly as much as they need.

Fortunately, every present is a box (a perfect right rectangular prism), which makes calculating the required wrapping paper for each gift a little easier: find the surface area of the box, which is 2*l*w + 2*w*h + 2*h*l. The elves also need a little extra paper for each present: the area of the smallest side.

For example:

  • A present with dimensions 2x3x4 requires 2*6 + 2*12 + 2*8 = 52 square feet of wrapping paper plus 6 square feet of slack, for a total of 58 square feet.
  • A present with dimensions 1x1x10 requires 2*1 + 2*10 + 2*10 = 42 square feet of wrapping paper plus 1 square foot of slack, for a total of 43 square feet.

All numbers in the elves' list are in feet. How many total square feet of wrapping paper should they order?

--- Part Two ---

The elves are also running low on ribbon. Ribbon is all the same width, so they only have to worry about the length they need to order, which they would again like to be exact.

The ribbon required to wrap a present is the shortest distance around its sides, or the smallest perimeter of any one face. Each present also requires a bow made out of ribbon as well; the feet of ribbon required for the perfect bow is equal to the cubic feet of volume of the present. Don't ask how they tie the bow, though; they'll never tell.

For example:

  • A present with dimensions 2x3x4 requires 2+2+3+3 = 10 feet of ribbon to wrap the present plus 2*3*4 = 24 feet of ribbon for the bow, for a total of 34 feet.
  • A present with dimensions 1x1x10 requires 1+1+1+1 = 4 feet of ribbon to wrap the present plus 1*1*10 = 10 feet of ribbon for the bow, for a total of 14 feet.

How many total feet of ribbon should they order?

##My Thoughts

Day 2 picked things up a bit with a math based problem. Initially I was having problems with the input string itself, as it included non-numeric characters and new lines after every set of dimensions. After far too much time searching for ways to accept new lines in strings I discovered template strings (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/template_strings). How in the world did I live without knowing about template strings? Using these beauties made splitting up strings and concatenation with variables much much easier. After finally getting the input properly placed into my program, I finally got into the meat of the challenge. This challenge essentially wanted you to do some calculations on the right dimension at the right time. To do this I put every length, width, and height values into their own separate arrays and did calculations on them on every loop. All of these areas were added to a total which was used as the final answer.

Day 2 definitely picked up from Day 1, but was still very doable. I liked this type of challenge because it required me to look up some documentation, but the majority of the work was straight logic.