add: day19

src/bin/d19.rs

@@ -1,4 +1,3 @@
-
 use std::collections::{HashMap, HashSet};
 
 use advent_of_code_2024::{make_main, SResult};
@@ -15,43 +14,45 @@ fn solve(lines: Vec<String>) -> SResult<(usize, usize)> {
     // see if we can form it using shorter patterns. If we can, ignore it.
     patterns.sort_by(|a, b| a.len().cmp(&b.len()));
     // Stores a mapping of 'char' => (pattern, larger_patterns)
-    let mut new_patterns: HashMap<char, Vec<(&str, HashSet<&str>)>> = HashMap::default();
+    let mut new_patterns: Vec<(&str, HashSet<&str>)> = Vec::new();
     let mut small_patterns = HashSet::new();
     for pattern in &patterns {
-        if let Some(c) = rec(&pattern, &new_patterns, &mut memo) {
+        if let Some(c) = rec(&pattern, &new_patterns, &mut HashMap::new()) {
-            *memo.entry(&pattern).or_insert(0) = c + 1;
+            // At this point, we haven't loaded the larger patterns into the hashsets
+            // in the new_patterns, so we never check if it matches. We always
+            // add one to the computed value.
+            //*memo.entry(&pattern).or_insert(0) = c + 1;
         } else {
-            let start = pattern.chars().next().unwrap();
+            new_patterns.push((pattern, HashSet::new()));
-            new_patterns.entry(start).or_insert_with(Vec::new).push((pattern, HashSet::new()));
             small_patterns.insert(pattern);
         }
     }
 
-    for (_, v) in new_patterns.iter_mut() {
+    new_patterns.sort_by(|a, b| a.0.cmp(&b.0));
-        v.sort_by(|a, b| a.0.cmp(&b.0));
 
-        for v in v {
+    for v in &mut new_patterns {
-            for pattern in &patterns {
+        for pattern in &patterns {
-                if small_patterns.contains(pattern) {
+            if small_patterns.contains(pattern) {
-                    continue;
+                continue;
-                }
+            }
-                if let Some(_) = pattern.strip_prefix(v.0) {
+            if let Some(_) = pattern.strip_prefix(v.0) {
-                    v.1.insert(pattern);
+                v.1.insert(pattern);
-                }
             }
         }
     }
 
-    println!("Patterns: {:?}", new_patterns);
+    // Reset the memoization
+    let mut memo: HashMap<&str, usize> = HashMap::default();
+    memo.insert("", 1);
 
-    let mut memo_vec: Vec<(&str, usize)> = memo.clone().into_iter().collect();
+    for pattern in &patterns {
-    memo_vec.sort_by(|a, b| a.0.cmp(&b.0));
+        rec(&pattern, &new_patterns, &mut memo);
-    println!("Memo: {:?}", memo_vec);
+    }
 
     let mut count = 0;
     let mut count2 = 0;
     for (i, line) in (&lines[2..]).iter().enumerate() {
-        //println!("Line {} of {}", i, lines.len()-2);
+        println!("Line {} of {}", i, lines.len()-2);
         if let Some(c) = rec(&line, &new_patterns, &mut memo) {
             count += 1;
             count2 += c;
@@ -59,17 +60,19 @@ fn solve(lines: Vec<String>) -> SResult<(usize, usize)> {
     }
     let mut memo_vec: Vec<(&str, usize)> = memo.into_iter().collect();
     memo_vec.sort_by(|a, b| a.0.cmp(&b.0));
-    println!("Memo: {:?}", memo_vec);
     Ok((count, count2))
 }
 
-fn rec<'a>(left: &'a str, patterns: &HashMap<char, Vec<(&'a str, HashSet<&'a str>)>>, memo: &mut HashMap<&'a str, usize>) -> Option<usize> {
+fn rec<'a>(
+    left: &'a str,
+    patterns: &Vec<(&'a str, HashSet<&'a str>)>,
+    memo: &mut HashMap<&'a str, usize>,
+) -> Option<usize> {
     if let Some(val) = memo.get(&left) {
         return Some(*val);
     }
     let mut count = 0;
-    let start = left.chars().next().unwrap();
+    for (pattern, large_patterns) in patterns {
-    for (pattern, large_patterns) in patterns.get(&start).unwrap_or(&vec!()) {
         if let Some(substr) = left.strip_prefix(pattern) {
             if let Some(c) = rec(substr, patterns, memo) {
                 count += c;