consize

Author: BKarthik7

src/greedy/stable_matching.rs

@@ -4,6 +4,33 @@ pub fn stable_matching(
     men_preferences: &HashMap<String, Vec<String>>,
     women_preferences: &HashMap<String, Vec<String>>,
 ) -> HashMap<String, String> {
+    let (mut free_men, mut current_partner, mut man_engaged, mut next_proposal) =
+        initialize_data_structures(men_preferences, women_preferences);
+
+    while let Some(man) = free_men.pop_front() {
+        handle_proposal(
+            &man,
+            &mut free_men,
+            &mut current_partner,
+            &mut man_engaged,
+            &mut next_proposal,
+            men_preferences,
+            women_preferences,
+        );
+    }
+
+    extract_stable_matches(man_engaged)
+}
+
+fn initialize_data_structures(
+    men_preferences: &HashMap<String, Vec<String>>,
+    women_preferences: &HashMap<String, Vec<String>>,
+) -> (
+    VecDeque<String>,
+    HashMap<String, Option<String>>,
+    HashMap<String, Option<String>>,
+    HashMap<String, usize>,
+) {
     let mut free_men: VecDeque<String> = VecDeque::new();
     let mut current_partner: HashMap<String, Option<String>> = HashMap::new();
     let mut man_engaged: HashMap<String, Option<String>> = HashMap::new();
@@ -18,48 +45,76 @@ pub fn stable_matching(
         current_partner.insert(woman.clone(), None);
     }
 
-    fn woman_prefers_new_man(
-        woman: &str,
-        man1: &str,
-        man2: &str,
-        preferences: &HashMap<String, Vec<String>>,
-    ) -> bool {
-        let woman_preferences = &preferences[woman];
-        woman_preferences.iter().position(|m| m == man1).unwrap()
-            < woman_preferences.iter().position(|m| m == man2).unwrap()
-    }
+    (free_men, current_partner, man_engaged, next_proposal)
+}
 
-    while let Some(man) = free_men.pop_front() {
-        let man_pref_list = &men_preferences[&man];
-        let next_woman_idx = *next_proposal.get(&man).unwrap();
-        let woman = &man_pref_list[next_woman_idx];
-
-        next_proposal.insert(man.clone(), next_woman_idx + 1);
-
-        if let Some(current_man) = current_partner[woman].clone() {
-            if woman_prefers_new_man(woman, &man, &current_man, women_preferences) {
-                man_engaged.insert(man.clone(), Some(woman.clone()));
-                current_partner.insert(woman.clone(), Some(man.clone()));
-                free_men.push_back(current_man);
-            } else {
-                free_men.push_back(man);
-            }
+fn handle_proposal(
+    man: &str,
+    free_men: &mut VecDeque<String>,
+    current_partner: &mut HashMap<String, Option<String>>,
+    man_engaged: &mut HashMap<String, Option<String>>,
+    next_proposal: &mut HashMap<String, usize>,
+    men_preferences: &HashMap<String, Vec<String>>,
+    women_preferences: &HashMap<String, Vec<String>>,
+) {
+    let man_pref_list = &men_preferences[man];
+    let next_woman_idx = *next_proposal.get(man).unwrap();
+    let woman = &man_pref_list[next_woman_idx];
+
+    next_proposal.insert(man.to_string(), next_woman_idx + 1);
+
+    if let Some(current_man) = current_partner[woman].clone() {
+        if woman_prefers_new_man(woman, man, &current_man, women_preferences) {
+            update_engagement(
+                man,
+                woman,
+                current_man,
+                free_men,
+                current_partner,
+                man_engaged,
+            );
         } else {
-            man_engaged.insert(man.clone(), Some(woman.clone()));
-            current_partner.insert(woman.clone(), Some(man.clone()));
+            free_men.push_back(man.to_string());
         }
+    } else {
+        man_engaged.insert(man.to_string(), Some(woman.to_string()));
+        current_partner.insert(woman.to_string(), Some(man.to_string()));
     }
+}
+
+fn update_engagement(
+    man: &str,
+    woman: &str,
+    current_man: String,
+    free_men: &mut VecDeque<String>,
+    current_partner: &mut HashMap<String, Option<String>>,
+    man_engaged: &mut HashMap<String, Option<String>>,
+) {
+    man_engaged.insert(man.to_string(), Some(woman.to_string()));
+    current_partner.insert(woman.to_string(), Some(man.to_string()));
+    free_men.push_back(current_man);
+}
+
+fn woman_prefers_new_man(
+    woman: &str,
+    man1: &str,
+    man2: &str,
+    preferences: &HashMap<String, Vec<String>>,
+) -> bool {
+    let woman_preferences = &preferences[woman];
+    woman_preferences.iter().position(|m| m == man1).unwrap()
+        < woman_preferences.iter().position(|m| m == man2).unwrap()
+}
 
-    let mut stable_matches: HashMap<String, String> = HashMap::new();
+fn extract_stable_matches(man_engaged: HashMap<String, Option<String>>) -> HashMap<String, String> {
+    let mut stable_matches = HashMap::new();
     for (man, woman_option) in man_engaged {
         if let Some(woman) = woman_option {
             stable_matches.insert(man, woman);
         }
     }
-
     stable_matches
 }
-
 #[cfg(test)]
 mod tests {
     use super::*;