Full solution for today (spoilers!)
Given a list of terms, repeatedly calculate the differences of terms until these differences are 0. So:
0 3 6 9 12 15 3 3 3 3 3 0 0 0 0Calculate the sum of next terms for each sequence (18 for this one).
Full solution for today (spoilers!)
Given a (repeated) sequence of moves (
Lfor left andRfor right) and a directed graph where each node has two neighbors (left and right), count how many total steps it takes to get from the nodeAAAto the nodeZZZ. The sequence of moves can (and will) need to repeat.
Full solution for today (spoilers!)
Simulate a limited poker game with no suits and break otherwise tied hands lexicographically (
AAAA2beatsAKAAA) because the the hands are both four of a kind, the first cards are bothA, but the secondAbeats theK. It doesn’t matter that the first hand’s off card was a2Order all hands then calculate the sum of the ordering of hands (1 for best etc) times the bet for each.
Full solution for today (spoilers!)
Simulate charging up race boats with the behavior that waiting X seconds to start means you move at X units per second. Given time allowed and a target distance, determine how many (integer) numbers of seconds will beat the target distance.
Full solution for today (spoilers!)
You are given a set of initial values (seeds) and a series of range maps (where a range of numbers
src..src+lenmaps todst..dst+len). Apply each range map in tur, return the lowest resulting value.
Full solution for today (spoilers!). Note: I did slightly change my solutions template after writing this blog post, so the final solution is structured slightly differently than the code in this post. The functionality itself hasn’t changed.
Simulate scratchcards. Given a list of winning numbers and guessed numbers, count how many guessed numbers are in the winning list. Your score is 1, 2, 4, 8, … for 1, 2, 3, 4, … matching numbers.
Full solution for today (spoilers!). Note: I did slightly change my solutions template after writing this blog post, so the final solution is structured slightly differently than the code in this post. The functionality itself hasn’t changed.
Take as input a 2D grid of numbers or symbols (
.represents empty space). Numbers will be 1 or more digits written horizontally which should be concatenated (.467*is the number467followed by the symbol*).Sum all numbers that are adjacent (including diagonally) to at least one symbol.
Full solution for today (spoilers!). Note: I did slightly change my solutions template after writing this blog post, so the final solution is structured slightly differently than the code in this post. The functionality itself hasn’t changed.
Play a game where you have some number of red, green, and blue dice in a cup, which you draw and roll (without replacement). Which game is possible with only 12 red, 13 gree, and 14 blue cubes?
Input will look like: Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
Full solution for today (spoilers!). Note: I did slightly change my solutions template after writing this blog post, so the final solution is structured slightly differently than the code in this post. The functionality itself hasn’t changed.
Given a list of alphanumeric strings, find the first and last digit on each line (they may be the same). Concatenate each pair and sum them.
Another year, another Advent of Code.
Like last year, we’re doing Rust. I’ve really grown to love the language since last year… and hopefully I’ve learned a bit more about how to write more ‘proper’ Rust. I know I had some issues last year. Functional… but it could be better.
Let’s see how it goes!
For full solutions, as always, I post to GitHub (including previous years and possibly some I haven’t written up yet): jpverkamp/advent-of-code