From 612bd4313fc2645146fc378098ab78f2ffc38727 Mon Sep 17 00:00:00 2001
From: Samuel Ortion <samuel@ortion.fr>
Date: Wed, 4 Dec 2024 12:52:52 +0100
Subject: [PATCH] day 2: part2: rust

---
 2024/days/02/part2/Cargo.toml  |  6 +++
 2024/days/02/part2/src/main.rs | 73 ++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 2024/days/02/part2/Cargo.toml
 create mode 100644 2024/days/02/part2/src/main.rs

diff --git a/2024/days/02/part2/Cargo.toml b/2024/days/02/part2/Cargo.toml
new file mode 100644
index 0000000..d85b608
--- /dev/null
+++ b/2024/days/02/part2/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "part1"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/2024/days/02/part2/src/main.rs b/2024/days/02/part2/src/main.rs
new file mode 100644
index 0000000..e888c32
--- /dev/null
+++ b/2024/days/02/part2/src/main.rs
@@ -0,0 +1,73 @@
+use std::u64;
+
+
+fn is_increasing(levels: &Vec<u64>) -> bool {
+    let mut current = 0;
+    for item in levels {
+        if *item < current {
+            return false;
+        } else {
+            current = *item;
+        }
+    }
+    return true;
+}
+
+fn is_decreasing(levels: &Vec<u64>) -> bool {
+    let mut current = u64::MAX;
+    for item in levels {
+        if *item > current {
+            return false;
+        } else {
+            current = *item;
+        }
+    }
+    return true;
+}
+
+fn is_monotonous(levels: &Vec<u64>) -> bool {
+    return is_increasing(levels) || is_decreasing(levels);
+}
+
+fn is_safe(levels: &Vec<u64>) -> bool {
+    if !is_monotonous(levels) {
+        return false;
+    }
+    for i in 0..(levels.len() - 1) {
+        let j = i+1;
+        let a = levels[i];
+        let b = levels[j];
+        let diff = (a as i64 - b as i64).abs() as u64;
+        if diff < 1 || diff > 3 {
+            return false;
+        }
+    }
+    return true;
+}
+
+fn is_safe_but_one(levels: &Vec<u64>) -> bool {
+    if is_safe(levels) {
+        return true;
+    }
+    for i in 0..(levels.len()) {
+        let mut levels_but_one = levels.clone();
+        levels_but_one.remove(i);
+        if is_safe(&levels_but_one) {
+            return true;
+        }
+    }
+    return false;
+}
+
+fn main() -> std::io::Result<()> {
+    let mut count = 0;
+    for line in std::io::stdin().lines() {
+        let line = line.unwrap();
+        let levels: Vec<u64> = line.split(" ").map(|x| x.parse::<u64>().unwrap()).collect();
+        if is_safe_but_one(&levels) {
+            count += 1;
+        }
+    }
+    println!("{}", count);
+    Ok(())
+}
\ No newline at end of file