day 2: part2: rust

2024/days/02/part2/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "part1"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

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(())
+}