solved day 5

day05/example.txt

@@ -1,9 +1,13 @@
-ugknbfddgicrmopn
+#ugknbfddgicrmopn
-aaa
+#aaa
-jchzalrnumimnmhp
+#jchzalrnumimnmhp
-haegwjzuvuyypxyu
+#haegwjzuvuyypxyu
-dvszwmarrgswjxmb
+#dvszwmarrgswjxmb
-qjhvhtzxzqqjkmpb
+
-xxyxx
+#qjhvhtzxzqqjkmpb
-uurcxstgmygtbstg
+#xxyxx
-ieodomkazucvgmuy
+#uurcxstgmygtbstg
+#ieodomkazucvgmuy
+#aaa
+xyxy
+#aabcdefgaa

day05/src/main.rs

@@ -14,14 +14,18 @@ fn main() {
 }
 
 fn part_1_and_2<T: Fn(&&str) -> bool>(data: &str, f: T) {
-    let sum = data.lines().filter(f).count();
+    let sum = data
+        .lines()
+        .filter(|line| !line.starts_with('#'))
+        .filter(f)
+        .count();
     println!("{sum}");
 }
 
 fn is_nice_1(s: &&str) -> bool {
     let vowel_count = s.chars().filter(|c| VOWELS.contains(*c)).count();
 
-    let double_letter = s.chars().zip(s.chars().skip(1)).any(|(a, b)| a == b);
+    let has_double_letter = s.chars().zip(s.chars().skip(1)).any(|(a, b)| a == b);
 
     let has_forbidden_tuple = s
         .chars()
@@ -29,14 +33,53 @@ fn is_nice_1(s: &&str) -> bool {
         .map(|(a, b)| format!("{a}{b}"))
         .any(|tuple| FORBIDDEN.contains(&tuple.as_str()));
 
-    vowel_count >= 3 && double_letter && !has_forbidden_tuple
+    vowel_count >= 3 && has_double_letter && !has_forbidden_tuple
 }
 
 fn is_nice_2(s: &&str) -> bool {
     let mut subrule_1 = false;
-    let mut subrule_2 = false;
+
+    let mut digraphs = extract_digraphs(s);
+
+    digraphs.sort_unstable();
+
+    let double_digraphs = digraphs
+        .iter()
+        .zip(digraphs.iter().skip(1))
+        .filter(|(a, b)| a == b)
+        .map(|(a, _)| a.clone());
+
+    for dd in double_digraphs {
+        // can't use the other one again because we
+        // need it unsorted here
+        let digraphs = extract_digraphs(s);
+
+        let mut iter = digraphs.into_iter();
+        let idx1 = iter.position(|x| x == *dd).unwrap();
+        let idx2 = iter.position(|x| x == *dd).unwrap() + idx1 + 1;
+
+        if idx2.abs_diff(idx1) >= 2 {
+            subrule_1 = true;
+            break;
+        }
+    }
+
+    let repeated_letter = s
+        .chars()
+        .zip(s.chars().skip(2))
+        .find(|(a, b)| a == b)
+        .map(|(a, _)| a);
+
+    let subrule_2 = repeated_letter.is_some();
 
     subrule_1 && subrule_2
 }
 
+fn extract_digraphs(s: &&str) -> Vec<String> {
+    s.chars()
+        .zip(s.chars().skip(1))
+        .map(|(a, b)| format!("{a}{b}"))
+        .collect()
+}
+
 // https://adventofcode.com/2015/day/5