add until day05-1

day04/Cargo.lock

@@ -0,0 +1,16 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "day04"
+version = "0.1.0"
+dependencies = [
+ "md5",
+]
+
+[[package]]
+name = "md5"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae960838283323069879657ca3de837e9f7bbb4c7bf6ea7f1b290d5e9476d2e0"

day04/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "day04"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+md5 = "0.8.0"

day04/example.txt

@@ -0,0 +1 @@
+abcdef

day04/input.txt

@@ -0,0 +1 @@
+yzbqklnj

day04/src/main.rs

@@ -0,0 +1,27 @@
+#[cfg(debug_assertions)]
+const FILENAME: &str = "example.txt";
+#[cfg(not(debug_assertions))]
+const FILENAME: &str = "input.txt";
+
+fn main() {
+    let data = std::fs::read_to_string(FILENAME).unwrap();
+
+    part_1_and_2(data.trim(), 5);
+    part_1_and_2(data.trim(), 6);
+}
+
+fn part_1_and_2(key: &str, length: usize) {
+    for i in 1.. {
+        let mut input = String::from(key);
+        input.push_str(&i.to_string());
+
+        let hash = md5::compute(input);
+
+        let hash_str = format!("{:x?}", hash);
+
+        if hash_str.chars().take(length).all(|c| c == '0') {
+            println!("{i}");
+            break;
+        }
+    }
+}