[2023/Rust/Day4] complete part 1

2023/rust/src/day4/mod.rs

@@ -0,0 +1,79 @@
+use nom::{
+    bytes::complete::tag,
+    character::complete::{self, digit1, space1},
+    multi::{many1, separated_list1},
+    sequence::{delimited, preceded, terminated},
+};
+
+use crate::utils;
+
+pub fn part_1() {
+    if let Ok(lines) = utils::read_lines("./puzzle_inputs/day4.txt") {
+        let cards: Vec<Card> = lines.flatten().filter_map(parse_card).collect();
+
+        let points = cards.iter().map(|card| {
+            let mut points = 0;
+
+            for player_value in &card.player_values {
+                if card.winning_values.contains(player_value) {
+                    if points == 0 {
+                        points = 1;
+                    } else {
+                        points *= 2;
+                    }
+                }
+            }
+
+            points
+        });
+
+        println!("Day 4 Part 1 solution: {:?}", points.sum::<i32>());
+    }
+}
+
+fn parse_card(line: String) -> Option<Card> {
+    if let Ok((card_values_input, _)) = delimited(
+        tag("Card"),
+        preceded(space1, digit1::<&str, nom::error::Error<&str>>),
+        terminated(complete::char(':'), many1(complete::char(' '))),
+    )(&line)
+    {
+        if let Ok((_, card_values)) = separated_list1(
+            delimited(
+                many1(complete::char(' ')),
+                complete::char('|'),
+                many1(complete::char(' ')),
+            ),
+            separated_list1(
+                many1(complete::char(' ')),
+                digit1::<&str, nom::error::Error<&str>>,
+            ),
+        )(card_values_input)
+        {
+            if card_values.len() != 2 {
+                panic!("The input is supposed to have 2 lists: 1 of winning values and 1 of player values.");
+            }
+
+            Some(Card {
+                winning_values: card_values[0]
+                    .iter()
+                    .filter_map(|v| v.parse::<i32>().ok())
+                    .collect(),
+                player_values: card_values[1]
+                    .iter()
+                    .filter_map(|v| v.parse::<i32>().ok())
+                    .collect(),
+            })
+        } else {
+            None
+        }
+    } else {
+        None
+    }
+}
+
+#[derive(Debug)]
+struct Card {
+    winning_values: Vec<i32>,
+    player_values: Vec<i32>,
+}

2023/rust/src/main.rs

@@ -1,6 +1,7 @@
 mod day1;
 mod day2;
 mod day3;
+mod day4;
 mod utils;
 
 fn main() {
@@ -12,4 +13,6 @@ fn main() {
 
     day3::part_1();
     day3::part_2();
+
+    day4::part_1();
 }