day06.md

— Day 6: Custom Customs —

Fleur Kelpin Dec 6, 2020

library(tidyverse)
input <- readr::read_file("day06.txt") %>%
  str_split("\n\n") %>%
  unlist()
tibble(input)

## # A tibble: 460 x 1
##    input                                                                     
##    <chr>                                                                     
##  1 "nefaym\neynamf\neafnmy\nafnmey"                                          
##  2 "zmd\nalo\nekvrtpyuqi\nhwmc\nszgah"                                       
##  3 "y\nmzqys\nycsq\nyrtxvnkdglj"                                             
##  4 "egubpzyrhlojkixfn\nhyifblockgenrzjxp\nzxgbkohlpyfjinre\nrzolbfihpkxnygje"
##  5 "wvjoehlkxnyz\nevwkobnhy\nnerkyowgv\ntaypknsdovmuwice\nqjvknewory"        
##  6 "ncypkuxsizla\nndjoiqhetrgmwfvb"                                          
##  7 "tfhnk\nkmnftzh\nhkntf\nnftkh"                                            
##  8 "wj\nw\nw\nwq\nw"                                                         
##  9 "jzaw\njzw"                                                               
## 10 "gysdxblojkvnmr\nkhymldnxgtbvirj\nbydgmxwjvrkfln\nlykvumdnrxbjg"          
## # … with 450 more rows

Part 1

For each group, count the number of questions to which anyone answered “yes”. What is the sum of those counts?

input %>%
  str_match_all("\\w") %>%
  map_dbl(
    ~ unique(.) %>%
      length()
  ) %>%
  sum()

## [1] 6259

Part 2

For each group, count the number of questions to which everyone answered “yes”. What is the sum of those counts?

input %>%
  str_split("\n") %>%
  map_dbl(
    ~ str_split(., "") %>%
      reduce(intersect) %>%
      length()
  ) %>%
  sum()

## [1] 3178