[TASK] Some small performance improvements in day 7 (like that was needed)

src/day7.rs

@@ -1,14 +1,17 @@
 use super::util;
 use regex::{Regex, Captures};
 use std::collections::{HashMap, HashSet, VecDeque};
+use std::time::Instant;
 
 pub fn solve() {
+    let now = Instant::now();
     let lines = util::read_file("input/day7.txt");
     let rules = lines.iter()
         .map(|s| Rule::parse(s))
         // .inspect(|r| println!("{:?}", r))
         .collect::<Vec<_>>();
 
+
     let mut reverse_rules: HashMap<String, Vec<&Rule>> = HashMap::new();
     for rule in &rules {
 
@@ -17,64 +20,62 @@ pub fn solve() {
         }
     }
 
-    let enclosing_bag_colors = find_enclosing_bag_colors("shiny gold", &reverse_rules);
+    let enclosing_bag_colors = find_enclosing_bag_colors(&String::from("shiny gold"), &reverse_rules);
 
-    println!("Day 7 Part 1: {}", enclosing_bag_colors.len());
+    println!("Day 7 Part 1: {}", enclosing_bag_colors);
 
     let part2 = count_bags("shiny gold", &rules);
     println!("Day 7 Part 2: {}", part2 - 1);
+    println!("Algo's took {} μs", now.elapsed().as_micros());
+
 }
 
-fn find_enclosing_bag_colors(root_color: &str, reverse_rules: &HashMap<String, Vec<&Rule>>) -> HashSet<String> {
-    let mut enclosing_bag_colors: HashSet<String> = HashSet::new();
-    let mut marked_colors: HashSet<String> = HashSet::new();
+fn find_enclosing_bag_colors(root_color: &String, reverse_rules: &HashMap<String, Vec<&Rule>>) -> usize {
 
-    let mut colors_to_check: VecDeque<String> = VecDeque::new();
-    colors_to_check.push_front(String::from(root_color));
+    let mut enclosing_bag_colors: HashSet<&String> = HashSet::new();
 
-    let empty: Vec<&Rule> = Vec::new();
+    let mut colors_to_check: VecDeque<&String> = VecDeque::new();
+    colors_to_check.push_front(root_color);
 
     while !colors_to_check.is_empty() {
         let cur = colors_to_check.pop_back().unwrap();
-        marked_colors.insert(String::from(&cur));
 
-        let cur_rules = reverse_rules.get(&cur).unwrap_or(&empty);
-        for rule in cur_rules {
-            let rule_color = String::from(&rule.bag_color);
+        let cur_rules = reverse_rules.get(cur);
+        if cur_rules.is_none() {
+            continue;
+        }
+        for rule in cur_rules.unwrap() {
+            let rule_color = &rule.bag_color;
 
-            if !marked_colors.contains(&rule_color) {
-                colors_to_check.push_front(String::from(&rule_color));
-            };
-            marked_colors.insert(String::from(&rule_color));
-            enclosing_bag_colors.insert(String::from(&rule_color));
+            colors_to_check.push_front(&rule_color);
+            enclosing_bag_colors.insert(&rule_color);
         }
     }
-    enclosing_bag_colors
+    enclosing_bag_colors.len()
 }
 
 fn count_bags(root_color: &str, rules: &Vec<Rule>) -> usize {
 
     // Let's first create a dictionary to easily find the rules for each colored bag
     let mut rule_map: HashMap<&String, &Rule> = HashMap::new();
-    for rule in rules {
-        rule_map.insert(&rule.bag_color, &rule);
-    }
+    rules.iter().for_each(|r: &Rule| -> () { rule_map.insert(&r.bag_color, &r); });
 
-    let root = String::from(root_color);
     let mut cache: HashMap<String, usize> = HashMap::new();
 
-    let res = count_bags_recursive( &root, &rule_map, &mut cache);
+    let res = count_bags_recursive( &String::from(root_color), &rule_map, &mut cache);
     // println!("{:?}", cache);
     res
 }
 
 fn count_bags_recursive(root_color: &String, rule_map: &HashMap<&String, &Rule>, cache: &mut HashMap<String, usize>) -> usize {
 
-    let rule = rule_map.get(&root_color).unwrap();
     let cached = cache.get(root_color);
-    return if cached.is_some() {
-        *cached.unwrap()
-    } else if rule.contains.is_empty() {
+    if cached.is_some() {
+        return *cached.unwrap()
+    }
+
+    let rule = rule_map.get(&root_color).unwrap();
+    return if rule.contains.is_empty() {
         cache.insert(String::from(root_color), 1);
         1
     } else {