103 lines
2.3 KiB
Rust
103 lines
2.3 KiB
Rust
fn get_split_rucksack_items(list: &str) -> (Vec<char>, Vec<char>) {
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let all_chars: Vec<_> = list.chars().collect();
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let half_index = all_chars.len() / 2;
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let halves = all_chars.split_at(half_index);
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assert_eq!(halves.0.len(), halves.1.len());
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(halves.0.to_vec(), halves.1.to_vec())
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}
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fn get_rucksack_items(list: &str) -> Vec<char> {
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list.chars().collect()
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}
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fn get_priority(item: char) -> u32 {
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let is_uppercase = item.is_ascii_uppercase();
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let char = if is_uppercase {
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item.to_ascii_lowercase()
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} else {
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item
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};
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let priority = match char {
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'a' => 1,
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'b' => 2,
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'c' => 3,
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'd' => 4,
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'e' => 5,
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'f' => 6,
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'g' => 7,
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'h' => 8,
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'i' => 9,
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'j' => 10,
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'k' => 11,
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'l' => 12,
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'm' => 13,
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'n' => 14,
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'o' => 15,
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'p' => 16,
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'q' => 17,
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'r' => 18,
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's' => 19,
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't' => 20,
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'u' => 21,
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'v' => 22,
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'w' => 23,
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'x' => 24,
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'y' => 25,
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'z' => 26,
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_ => 0,
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};
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if is_uppercase {
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priority + 26
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} else {
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priority
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}
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}
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fn find_same_item(a: Vec<char>, b: Vec<char>) -> char {
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for ch in a {
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if b.contains(&ch) {
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return ch;
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}
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}
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panic!("We should have already found the item")
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}
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fn find_same_item_in_three(a: &Vec<char>, b: &Vec<char>, c: &Vec<char>) -> char {
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for ch in a {
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if b.contains(&ch) && c.contains(&ch) {
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return *ch;
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}
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}
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panic!("We should have already found the common item");
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}
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fn main() {
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let file_str = include_str!("input.txt");
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let sum: u32 = file_str
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.lines()
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.map(|line| get_split_rucksack_items(line))
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.map(|(a, b)| find_same_item(a, b))
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.map(|item| get_priority(item))
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.sum();
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let sacks: Vec<Vec<char>> = file_str
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.lines()
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.map(|line| get_rucksack_items(line))
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.collect();
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let group_sum: u32 = sacks
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.chunks(3)
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.map(|chunk| find_same_item_in_three(&chunk[0], &chunk[1], &chunk[2]))
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.map(|item| get_priority(item))
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.sum();
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println!("Part 1 Priority Sum: {}", sum);
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println!("Part 2 Group Sum: {}", group_sum);
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}
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