input <- readr::read_delim(
"2024/01-input",
delim = " ",
col_names = FALSE,
show_col_types = FALSE
)
sum(abs(sort(input$X1) - sort(input$X2)))0.076 sec elapsedinput <- readr::read_delim(
"2024/01-input",
delim = " ",
col_names = FALSE,
show_col_types = FALSE
)
counts <- table(input$X2)[as.character(input$X1)]
sum(abs(input$X1 * counts), na.rm = TRUE)0.005 sec elapsedread_list <- function(path, sep = "", type = identity) {
lines <- readLines(path)
res <- strsplit(lines, sep)
res <- lapply(res, type)
res
}
input <- read_list("2024/02-input", " ", as.integer)
safe <- function(x) {
diffs <- diff(x)
cond1 <- all(diffs > 0) || all(diffs < 0)
cond2 <- all(abs(diffs) >= 1) && all(abs(diffs) <= 3)
cond1 && cond2
}
vapply(input, safe, logical(1)) |>
sum()0.033 sec elapsedread_list <- function(path, sep = "", type = identity) {
lines <- readLines(path)
res <- strsplit(lines, sep)
res <- lapply(res, type)
res
}
input <- read_list("2024/02-input", " ", as.integer)
safe <- function(x) {
diffs <- diff(x)
cond1 <- all(diffs > 0) || all(diffs < 0)
cond2 <- all(abs(diffs) >= 1) && all(abs(diffs) <= 3)
cond1 && cond2
}
skip_safe <- function(x) {
is_safe <- FALSE
for (i in seq_along(x)) {
if (safe(x[-i])) {
is_safe <- TRUE
break
}
}
is_safe
}
vapply(input, skip_safe, logical(1)) |>
sum()0.024 sec elapsed0.024 sec elapsedinput <- readLines("2024/03-input") |>
paste0(collapse = "")
mul <- function(x, y) x * y
input |>
stringr::str_remove_all("don't\\(\\).*?do\\(\\)") |>
stringr::str_extract_all("mul\\(\\d+,\\d+\\)") |>
unlist() |>
purrr::map_int(\(x) eval(parse(text = x))) |>
sum()0.015 sec elapsedread_matrix <- function(path, sep = "", fill = NA, type = identity) {
lines <- readLines(path)
tokens <- strsplit(lines, sep)
token_lengths <- lengths(tokens)
res <- matrix(fill, nrow = length(lines), ncol = max(token_lengths))
for (i in seq_along(lines)) {
res[i, seq_len(token_lengths[i])] <- type(tokens[[i]])
}
res
}
input <- read_matrix("2024/04-input")
up <- apply(input, 1, identity, simplify = FALSE)
down <- lapply(up, rev)
left <- apply(input, 2, identity, simplify = FALSE)
right <- lapply(left, rev)
nrow <- nrow(input)
diag1 <- purrr::map(seq(-nrow - 1, nrow - 1), \(i) input[row(input) == (col(input) + i)])
diag2 <- purrr::map(seq(2, nrow * 2), \(i) input[row(input) + col(input) == i])
diag3 <- lapply(diag1, rev)
diag4 <- lapply(diag2, rev)
c(left, right, up, down, diag1, diag2, diag3, diag4) |>
purrr::map_chr(\(x) paste(x, collapse = "")) |>
stringr::str_count("XMAS") |>
sum()0.119 sec elapsedread_matrix <- function(path, sep = "", fill = NA, type = identity) {
lines <- readLines(path)
tokens <- strsplit(lines, sep)
token_lengths <- lengths(tokens)
res <- matrix(fill, nrow = length(lines), ncol = max(token_lengths))
for (i in seq_along(lines)) {
res[i, seq_len(token_lengths[i])] <- type(tokens[[i]])
}
res
}
input <- read_matrix("2024/04-input")
a_loc <- reshape2::melt(input == "A") |>
dplyr::filter(value)
count <- 0
for (i in seq_len(nrow(a_loc))) {
vals <- a_loc[i, ]
x <- vals$Var1
y <- vals$Var2
if (x == 1 || x == nrow(input) || y == 1 || y == nrow(input)) {
next
}
x_values <- paste0(
input[x + 1, y + 1], input[x + 1, y - 1],
input[x - 1, y - 1], input[x - 1, y + 1],
collapse = ""
)
valid <- c("MMSS", "MSSM", "SSMM", "SMMS")
if (x_values %in% valid) {
count <- count + 1
}
}
count0.117 sec elapsedinput <- readLines("2024/05-input")
sep <- which(input == "")
rules <- input[seq(1, sep - 1)] |>
strsplit("\\|") |>
lapply(as.integer)
updates <- input[seq(sep + 1, length(input))] |>
strsplit(",") |>
lapply(as.integer)
pass_rule <- function(rule, update) {
order <- diff(match(rule, update))
is.na(order) || order > 0
}
pass_rules <- function(update, rules) {
all(vapply(rules, pass_rule, logical(1), update = update))
}
which_passes <- vapply(updates, pass_rules, logical(1), rules)
get_middle <- function(x) {
mid <- length(x) / 2 + 1
x[mid]
}
updates[which_passes] |>
lapply(get_middle) |>
unlist() |>
sum()0.812 sec elapsedinput <- readLines("2024/05-input")
sep <- which(input == "")
rules <- input[seq(1, sep - 1)] |>
strsplit("\\|") |>
lapply(as.integer)
updates <- input[seq(sep + 1, length(input))] |>
strsplit(",") |>
lapply(as.integer)
pass_rule <- function(rule, update) {
order <- diff(match(rule, update))
is.na(order) || order > 0
}
pass_rules <- function(update, rules) {
all(vapply(rules, pass_rule, logical(1), update = update))
}
which_passes <- vapply(updates, pass_rules, logical(1), rules)
get_middle <- function(x) {
mid <- length(x) / 2 + 1
x[mid]
}
uncorrect <- updates[!which_passes]
fix_order <- function(rule, update) {
matches <- match(rule, update)
before <- matches[1]
after <- matches[2]
before_inds <- setdiff(seq(1, before), after)
after_inds <- setdiff(seq_along(update), c(before_inds, after))
new_order <- c(before_inds, after, after_inds)
update[new_order]
}
fix_update <- function(update, rules) {
while (!pass_rules(update, rules)) {
for (rule in rules) {
if (pass_rule(rule, update)) {
next
}
update <- fix_order(rule, update)
}
}
update
}
uncorrect |>
lapply(fix_update, rules) |>
lapply(get_middle) |>
unlist() |>
sum()2.77 sec elapsed