Merge pull request #344 from paulcacheux/day2-2024

day 2 part 1 & 2

inputs/2024/day2_test.txt

@@ -0,0 +1,6 @@
+7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9

results/2024.json

@@ -3,5 +3,10 @@
         "day": 1,
         "part1": "1660292",
         "part2": "22776016"
+    },
+    {
+        "day": 2,
+        "part1": "502",
+        "part2": "544"
     }
 ]

src/aoc2024/day2.rs

@@ -0,0 +1,82 @@
+use itertools::Itertools;
+
+use crate::aoc2024::Aoc2024;
+use crate::traits::days::Day2;
+use crate::traits::ParseInput;
+use crate::traits::Solution;
+
+impl ParseInput<Day2> for Aoc2024 {
+    type Parsed = Vec<Vec<u32>>;
+
+    fn parse_input(input: &str) -> Self::Parsed {
+        let mut grid = Vec::new();
+        for line in input.lines() {
+            let mut row = Vec::new();
+            for num in line.split_whitespace() {
+                row.push(num.parse().unwrap());
+            }
+            grid.push(row);
+        }
+        grid
+    }
+}
+
+impl Solution<Day2> for Aoc2024 {
+    type Part1Output = u32;
+    type Part2Output = u32;
+
+    fn part1(input: &Vec<Vec<u32>>) -> u32 {
+        let mut safe = 0;
+        for line in input {
+            if safe_line(line) {
+                safe += 1;
+            }
+        }
+        safe
+    }
+
+    fn part2(input: &Vec<Vec<u32>>) -> u32 {
+        let mut safe = 0;
+        for line in input {
+            if safe_line(line) {
+                safe += 1;
+                continue;
+            }
+
+            for i in 0..line.len() {
+                let left = &line[..i];
+                let right = &line[i + 1..];
+                if safe_line2(left, right) {
+                    safe += 1;
+                    break;
+                }
+            }
+        }
+        safe
+    }
+}
+
+fn safe_line(line: &[u32]) -> bool {
+    safe_line2(line, &[])
+}
+
+fn safe_line2(left: &[u32], right: &[u32]) -> bool {
+    let mut ordering = None;
+
+    for (&l, &r) in left.iter().chain(right).tuple_windows() {
+        let diff = l.abs_diff(r);
+        if !(1..=3).contains(&diff) {
+            return false;
+        }
+
+        let current_ordering = l.cmp(&r);
+        if let Some(ordering) = ordering {
+            if ordering != current_ordering {
+                return false;
+            }
+        }
+        ordering = Some(current_ordering);
+    }
+
+    true
+}

src/aoc2024/mod.rs

@@ -4,6 +4,7 @@ use crate::traits::days::*;
 pub struct Aoc2024;
 
 pub mod day1;
+pub mod day2;
 
 pub fn run_solution_for_day(day: u32, input: &str, results: Option<Results>) -> Option<TimingData> {
     let r = results
@@ -12,6 +13,7 @@ pub fn run_solution_for_day(day: u32, input: &str, results: Option<Results>) ->
 
     let elapsed = match day {
         1 => run::<Aoc2024, Day1>(input, r),
+        2 => run::<Aoc2024, Day2>(input, r),
         _ => return None,
     };
     Some(elapsed)