Day 1

Advent of Code: Worked Solutions

Setup

# Libraries
library(tidyverse)

# Read input from file
input <- read_lines("../input/day01.txt") |> 
  as.integer()

Part 1

# Format input as a data frame and number the elves
df <- tibble(
  cal = input,
  elf_id = cumsum(is.na(cal)) + 1
) |>
  filter(!is.na(cal))

# Compute calorie sum for each elf, get the top n elves, and combine totals
count_max <- function(df, num_top_elves) {
  df |> 
    group_by(elf_id) |>
    summarize(total_cal = sum(cal)) |>
    slice_max(total_cal, n = num_top_elves) |>
    pull(total_cal) |>
    sum()
}

Run puzzle input:

count_max(df, 1)

[1] 68787

Part 2

count_max(df, 3)

[1] 198041