feat: day4

Signed-off-by: Louis Vallat <louis@louis-vallat.xyz>

.gitlab-ci.yml

@@ -18,3 +18,8 @@ day-3:
   stage: build
   script:
     - cd day3; cargo run --release ./input
+
+day-4:
+  stage: build
+  script:
+    - cd day4; cargo run --release ./input

day4/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "day3"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day4/src/main.rs

@@ -0,0 +1,33 @@
+use std::{fs, env, vec};
+
+
+fn read_input(path: &str) -> String {
+    return fs::read_to_string(path).expect("Cannot read file.");
+}
+
+fn parse_input(s: &str) -> Vec<((u32, u32), (u32, u32))> {
+    return s.lines().into_iter().fold(vec![], |mut acc, x| {
+        let numbers: Vec<u32> = x.split(&['-', ',']).map(|s| s.parse::<u32>().unwrap()).collect();
+        acc.push(((numbers[0], numbers[1]), (numbers[2], numbers[3])));
+        return acc;
+    });
+}
+
+fn fully_contains(t1: &(u32, u32), t2: &(u32, u32)) -> bool {
+    return (t1.0 >= t2.0 && t1.1 <= t2.1) || (t1.0 <= t2.0 && t1.1 >= t2.1);
+}
+
+fn partially_contains(t1: &(u32, u32), t2: &(u32, u32)) -> bool {
+    return (t2.0 <= t1.1 && t2.0 >= t1.0) || (t2.1 <= t1.1 && t2.1 >= t1.0);
+}
+
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    for arg in args.iter().skip(1) {
+        println!("[{}]", &arg);
+        let vec_in = parse_input(&read_input(&arg));
+        println!("\t[Part 1] => Answer is '{}'.", vec_in.iter().filter(|t| fully_contains(&t.0, &t.1)).count());
+        println!("\t[Part 2] => Answer is '{}'.", vec_in.iter().filter(|t| fully_contains(&t.0, &t.1) || partially_contains(&t.0, &t.1)).count());
+    }
+}