add day 14

day14/src/main.rs

@@ -0,0 +1,99 @@
+use std::collections::VecDeque;
+
+use itertools::Itertools;
+
+#[cfg(debug_assertions)]
+const INPUT: &str = "abc";
+#[cfg(not(debug_assertions))]
+const INPUT: &str = "ihaygndm";
+
+fn main() {
+    part_1();
+    part_2();
+}
+
+fn part_2() {
+    let mut next_hashes = VecDeque::new();
+
+    let mut idx = 0;
+    let mut found_key_counter = 0;
+
+    loop {
+        while next_hashes.len() < 1_000 {
+            next_hashes.push_back(calculate_hash_repeated(INPUT, idx, 2016));
+            idx += 1;
+        }
+
+        let this_hash = next_hashes.pop_front().unwrap();
+
+        if let Some(found_char) = find_triple_char(&this_hash)
+            && next_hashes
+                .iter()
+                .any(|s| contains_quintuple(s.as_str(), found_char))
+        {
+            found_key_counter += 1;
+            if found_key_counter == 64 {
+                println!("{}", idx - 1000);
+                break;
+            }
+        }
+    }
+}
+
+fn part_1() {
+    let mut next_hashes = VecDeque::new();
+
+    let mut idx = 0;
+    let mut found_key_counter = 0;
+
+    loop {
+        while next_hashes.len() < 1_000 {
+            next_hashes.push_back(calculate_hash(INPUT, idx));
+            idx += 1;
+        }
+
+        let this_hash = next_hashes.pop_front().unwrap();
+
+        if let Some(found_char) = find_triple_char(&this_hash)
+            && next_hashes
+                .iter()
+                .any(|s| contains_quintuple(s.as_str(), found_char))
+        {
+            found_key_counter += 1;
+            if found_key_counter == 64 {
+                println!("{}", idx - 1000);
+                break;
+            }
+        }
+    }
+}
+
+fn calculate_hash(s: &str, idx: usize) -> String {
+    format!("{:x}", md5::compute(format!("{s}{idx}")))
+}
+
+fn calculate_hash_repeated(s: &str, idx: usize, count: usize) -> String {
+    let mut hash = calculate_hash(s, idx);
+
+    for _ in 0..count {
+        hash = format!("{:x}", md5::compute(hash));
+    }
+
+    hash
+}
+
+fn find_triple_char(s: &str) -> Option<char> {
+    s.chars()
+        .tuple_windows()
+        .filter(|(a, b, c)| a == b && b == c)
+        .map(|(c, _, _)| c)
+        .next()
+}
+
+fn contains_quintuple(s: &str, value: char) -> bool {
+    s.chars().tuple_windows().any(|(a, b, c, d, e)| {
+        let head = a;
+        [b, c, d, e].into_iter().all(|ch| head == ch) // all items are identical
+            && head == value
+    })
+}