From 83c4ba70478aa7ce523254b774b16fb773a6a01f Mon Sep 17 00:00:00 2001
From: JamesPatrickGill <jpgilldev@gmail.com>
Date: Tue, 3 Dec 2024 19:44:23 +0000
Subject: [PATCH] day 2

---
 Cargo.lock           |  16 +++++++
 Cargo.toml           |   1 +
 README.md            |   9 ++--
 data/examples/02.txt |   6 +++
 src/bin/02.rs        | 106 +++++++++++++++++++++++++++++++++++++++++--
 5 files changed, 129 insertions(+), 9 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 9504be6..e8bbce6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -23,6 +23,7 @@ version = "0.11.0"
 dependencies = [
  "chrono",
  "dhat",
+ "itertools",
  "pico-args",
  "tinyjson",
 ]
@@ -126,6 +127,12 @@ dependencies = [
  "thousands",
 ]
 
+[[package]]
+name = "either"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
+
 [[package]]
 name = "gimli"
 version = "0.28.1"
@@ -155,6 +162,15 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.9"
diff --git a/Cargo.toml b/Cargo.toml
index 038a1a3..a80ffa7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -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"
 
diff --git a/README.md b/README.md
index ab5b3b6..f16200a 100644
--- a/README.md
+++ b/README.md
@@ -13,13 +13,12 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 <!--- advent_readme_stars table --->
 
 <!--- benchmarking table --->
-
 ## Benchmarks
 
-|           Day            |  Part 1  |  Part 2  |
-| :----------------------: | :------: | :------: |
+| Day | Part 1 | Part 2 |
+| :---: | :---: | :---:  |
 | [Day 1](./src/bin/01.rs) | `40.7µs` | `58.2µs` |
+| [Day 2](./src/bin/02.rs) | `117.1µs` | `205.3µs` |
 
-**Total: 0.10ms**
-
+**Total: 0.42ms**
 <!--- benchmarking table --->
diff --git a/data/examples/02.txt b/data/examples/02.txt
index e69de29..b49c10d 100644
--- a/data/examples/02.txt
+++ b/data/examples/02.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
diff --git a/src/bin/02.rs b/src/bin/02.rs
index 3bae35c..7e23508 100644
--- a/src/bin/02.rs
+++ b/src/bin/02.rs
@@ -1,11 +1,109 @@
+use std::collections::VecDeque;
+
+use itertools::Itertools;
+
 advent_of_code::solution!(2);
 
 pub fn part_one(input: &str) -> Option<u32> {
-    None
+    let reports = input
+        .lines()
+        .map(|line| {
+            line.split(" ")
+                .map(|a| a.parse::<i32>().unwrap())
+                .collect_vec()
+        })
+        .collect_vec();
+
+    let mut bad_reports = 0;
+    for report in reports.iter() {
+        let mut dir = 0;
+        for idx in 0..report.len() - 1 {
+            let l = report.get(idx).unwrap();
+            let r = report.get(idx + 1).unwrap();
+            match r.cmp(l) {
+                std::cmp::Ordering::Less => {
+                    if dir == 1 || l - r > 3 {
+                        bad_reports += 1;
+                        break;
+                    }
+                    dir = -1;
+                }
+                std::cmp::Ordering::Equal => {
+                    bad_reports += 1;
+                    break;
+                }
+                std::cmp::Ordering::Greater => {
+                    if dir == -1 || r - l > 3 {
+                        bad_reports += 1;
+                        break;
+                    }
+                    dir = 1;
+                }
+            }
+        }
+    }
+    Some((reports.len() - bad_reports) as u32)
 }
 
 pub fn part_two(input: &str) -> Option<u32> {
-    None
+    let reports = input
+        .lines()
+        .map(|line| {
+            line.split(" ")
+                .map(|a| a.parse::<i32>().unwrap())
+                .collect_vec()
+        })
+        .collect_vec();
+
+    let mut good_reports = 0;
+    for report in reports.iter() {
+        let mut to_check_queue = VecDeque::new();
+        to_check_queue.push_back(report);
+        while !to_check_queue.is_empty() {
+            if is_safe(report) {
+                good_reports += 1
+            } else {
+                for idx in 0..report.len() {
+                    let mut new_report = report.clone();
+                    new_report.remove(idx);
+                    if is_safe(&new_report) {
+                        good_reports += 1;
+                        break;
+                    }
+                }
+            };
+
+            to_check_queue.pop_front();
+        }
+    }
+
+    Some(good_reports)
+}
+
+fn is_safe(report: &[i32]) -> bool {
+    let mut dir = 0;
+    for idx in 0..report.len() - 1 {
+        let l = report.get(idx).unwrap();
+        let r = report.get(idx + 1).unwrap();
+        match r.cmp(l) {
+            std::cmp::Ordering::Less => {
+                if dir == 1 || l - r > 3 {
+                    return false;
+                }
+                dir = -1;
+            }
+            std::cmp::Ordering::Equal => {
+                return false;
+            }
+            std::cmp::Ordering::Greater => {
+                if dir == -1 || r - l > 3 {
+                    return false;
+                }
+                dir = 1;
+            }
+        }
+    }
+    true
 }
 
 #[cfg(test)]
@@ -15,12 +113,12 @@ mod tests {
     #[test]
     fn test_part_one() {
         let result = part_one(&advent_of_code::template::read_file("examples", DAY));
-        assert_eq!(result, None);
+        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, None);
+        assert_eq!(result, Some(4));
     }
 }