AOC 2021 Day 1

aoc2021_1.R

# Advent of Code
## Day 1

library(tidyverse)

### Practice

v <- 
  c("199", "200", "208", "210", "200", "207", "240", "269", "260", "263") %>% 
  as_tibble()

v %>% 
  mutate(measurement = case_when(lag(.) < . ~ "increased",
                                 lag(.) > . ~ "decreased",
                                 TRUE ~ "N/A")) %>% 
  group_by(measurement) %>% 
  tally()

### Real Thing

#### Part 1

input <-
  tibble(x = read_lines("/Users/shortessay/Desktop/aoc1_1.txt")) %>%
  mutate(x = as.numeric(x))

input %>%
  mutate(measurement = case_when(lag(.) < . ~ "increased",
                                 lag(.) > . ~ "decreased",
                                 TRUE ~ "N/A")) %>%
  group_by(measurement) %>%
  tally()

#### Part 2

input %>%
  mutate(measurement_sum = . + lead(., n = 1) + lead(., n = 2)) %>%
  mutate(
    measurement = case_when(
      lag(measurement_sum) < measurement_sum ~ "increased",
      lag(measurement_sum) > measurement_sum ~ "decreased",
      TRUE ~ "N/A"
    )
  ) %>%
  group_by(measurement) %>%
  tally()