AOC 2024 Day 02

Author: raul-sauco

aoc/2024/rust/Cargo.lock

@@ -24,6 +24,7 @@ test_lib = []
 # Template dependencies
 chrono = { version = "0.4.38", optional = true }
 dhat = { version = "0.3.3", optional = true }
+itertools = "0.13.0"
 pico-args = "0.5.0"
 tinyjson = "2.5.1"
 

aoc/2024/rust/Cargo.toml

@@ -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

aoc/2024/rust/data/examples/02.txt

@@ -0,0 +1,109 @@
+use itertools::Itertools;
+
+advent_of_code::solution!(2);
+
+pub fn part_one(input: &str) -> Option<u32> {
+    fn is_safe_report(report: &Vec<u32>) -> bool {
+        fn is_increasing(report: &Vec<u32>) -> bool {
+            for (a, b) in report.iter().tuple_windows() {
+                if a >= b || b - a > 3 {
+                    return false;
+                }
+            }
+            true
+        }
+        fn is_decreasing(report: &Vec<u32>) -> bool {
+            for (a, b) in report.iter().tuple_windows() {
+                if a <= b || a - b > 3 {
+                    return false;
+                }
+            }
+            true
+        }
+        is_increasing(report) || is_decreasing(report)
+    }
+    Some(
+        input
+            .lines()
+            .map(|line| {
+                let report = line
+                    .split_ascii_whitespace()
+                    .map(|s| s.parse::<u32>().expect("A valid number"))
+                    .collect::<Vec<_>>();
+                if is_safe_report(&report) {
+                    1
+                } else {
+                    0
+                }
+            })
+            .sum(),
+    )
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    fn is_safe_report(report: &Vec<u32>) -> bool {
+        fn is_increasing(report: &Vec<u32>) -> bool {
+            for (a, b) in report.iter().tuple_windows() {
+                if a >= b || b - a > 3 {
+                    return false;
+                }
+            }
+            true
+        }
+        fn is_decreasing(report: &Vec<u32>) -> bool {
+            for (a, b) in report.iter().tuple_windows() {
+                if a <= b || a - b > 3 {
+                    return false;
+                }
+            }
+            true
+        }
+        if is_increasing(report) || is_decreasing(report) {
+            return true;
+        }
+        for skip_idx in 0..report.len() {
+            let clone = report
+                .iter()
+                .enumerate()
+                .filter_map(|(idx, item)| if idx == skip_idx { None } else { Some(*item) })
+                .collect::<Vec<_>>();
+            if is_increasing(&clone) || is_decreasing(&clone) {
+                return true;
+            }
+        }
+        false
+    }
+    Some(
+        input
+            .lines()
+            .map(|line| {
+                let report = line
+                    .split_ascii_whitespace()
+                    .map(|s| s.parse::<u32>().expect("A valid number"))
+                    .collect::<Vec<_>>();
+                if is_safe_report(&report) {
+                    1
+                } else {
+                    0
+                }
+            })
+            .sum(),
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(2));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(4));
+    }
+}