solution: day5

Cargo.lock

@@ -32,6 +32,7 @@ dependencies = [
  "hex-literal",
  "itertools",
  "lazy_static",
+ "md-5",
  "pico-args",
  "regex",
  "reqwest",
@@ -56,6 +57,15 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "block-buffer"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cce20737498f97b993470a6e536b8523f0af7892a4f928cceb1ac5e52ebe7e"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.11.1"
@@ -96,6 +106,26 @@ version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5827cebf4670468b8772dd191856768aedcb1b0278a04f989f7766351917b9dc"
 
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[package]]
+name = "digest"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8168378f4e5023e7218c89c891c0fd8ecdb5e5e4f18cb78f38cf245dd021e76f"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+]
+
 [[package]]
 name = "dotenv"
 version = "0.15.0"
@@ -206,6 +236,16 @@ dependencies = [
  "pin-utils",
 ]
 
+[[package]]
+name = "generic-array"
+version = "0.14.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bff49e947297f3312447abdca79f45f4738097cc82b06e72054d2223f601f1b9"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
 [[package]]
 name = "h2"
 version = "0.3.15"
@@ -416,6 +456,15 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "md-5"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6365506850d44bff6e2fbcb5176cf63650e48bd45ef2fe2665ae1570e0f4b9ca"
+dependencies = [
+ "digest",
+]
+
 [[package]]
 name = "memchr"
 version = "2.5.0"
@@ -897,6 +946,12 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "59547bce71d9c38b83d9c0e92b6066c4253371f15005def0c30d9657f50c7642"
 
+[[package]]
+name = "typenum"
+version = "1.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "497961ef93d974e23eb6f433eb5fe1b7930b659f06d12dec6fc44a8f554c0bba"
+
 [[package]]
 name = "unicode-bidi"
 version = "0.3.8"

Cargo.toml

@@ -16,6 +16,7 @@ hashbrown = "0.13.1"
 hex-literal = "0.3.4"
 itertools = "0.10.5"
 lazy_static = "1.4.0"
+md-5 = "0.10.5"
 pico-args = "0.5.0"
 regex = "1.7.0"
 reqwest = "0.11.13"

src/bin/05.rs

@@ -0,0 +1,78 @@
+use hashbrown::HashMap;
+use itertools::Itertools;
+use md5::{Digest, Md5};
+
+pub fn part_one(input: &str) -> Option<String> {
+    let key = input.trim().as_bytes();
+    let mut hasher = Md5::new();
+    let mut count = 0;
+    let mut res = String::new();
+
+    for x in 0..std::u64::MAX {
+        hasher.update(key);
+        hasher.update(x.to_string().as_bytes());
+        let output = hasher.finalize_reset();
+
+        if output.starts_with(&[0, 0]) && output[2] <= 0x0F {
+            count += 1;
+            res.push_str(&format!("{:02x}", output[2])[1..]);
+        }
+
+        if count == 8 {
+            break;
+        }
+    }
+
+    Some(res)
+}
+pub fn part_two(input: &str) -> Option<String> {
+    let key = input.trim().as_bytes();
+    let mut hasher = Md5::new();
+    let mut res = HashMap::new();
+
+    for x in 0..std::u64::MAX {
+        hasher.update(key);
+        hasher.update(x.to_string().as_bytes());
+        let output = hasher.finalize_reset();
+
+        if output.starts_with(&[0, 0]) && output[2] <= 0x0F {
+            let (p, c) = format!("{:02x}{:02x}", output[2], output[3])[1..3]
+                .chars()
+                .next_tuple()
+                .unwrap();
+            if ('0'..='7').contains(&p) && !res.contains_key(&p) {
+                res.insert(p, c);
+            }
+        }
+
+        if res.len() == 8 {
+            break;
+        }
+    }
+
+    Some(
+        res.iter()
+            .sorted_by(|a, b| a.0.cmp(b.0))
+            .map(|(_, v)| v)
+            .collect(),
+    )
+}
+fn main() {
+    let input = &aoc::read_file("inputs", 5);
+    aoc::solve!(1, part_one, input);
+    aoc::solve!(2, part_two, input);
+}
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_part_one() {
+        let input = aoc::read_file("examples", 5);
+        assert_eq!(part_one(&input), Some("18f47a30".to_string()));
+    }
+    #[test]
+    fn test_part_two() {
+        let input = aoc::read_file("examples", 5);
+        assert_eq!(part_two(&input), Some("05ace8e3".to_string()));
+    }
+}

src/examples/05.txt

@@ -0,0 +1 @@
+abc