20240509 Finished

src/problem/mod.rs

@@ -125,4 +125,5 @@ mod p289_game_of_life;
 mod p383_ransom_note;
 mod p290_word_pattern;
 mod p205_isomorphic_strings;
-mod p242_valid_anagram;
+mod p242_valid_anagram;
+mod p49_group_anagrams;

src/problem/p49_group_anagrams.rs

@@ -0,0 +1,107 @@
+/**
+ * [49] Group Anagrams
+ */
+pub struct Solution {}
+
+// submission codes start here
+use std::{collections::HashMap, hash::Hash};
+
+#[derive(Debug)]
+struct WordState {
+    characters: HashMap<char, usize>,
+}
+
+impl PartialEq for WordState {
+    fn eq(&self, other: &Self) -> bool {
+        if self.characters.len() != other.characters.len() {
+            return false;
+        }
+
+        for (c, &v) in self.characters.iter() {
+            match other.characters.get(c) {
+                Some(other_v) => {
+                    if *other_v != v {
+                        return false;
+                    }
+                }
+                None => {
+                    return false;
+                }
+            }
+        }
+
+        true
+    }
+}
+
+impl Eq for WordState {}
+
+impl Hash for WordState {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        let mut chars: Vec<(&char, &usize)> = 
+            self.characters.iter().map(|p| p).collect();
+        
+        chars.sort_by_key(|p| p.0);
+
+        for (&c, &v) in chars {
+            c.hash(state);
+            v.hash(state);   
+        }
+    }
+}
+
+impl Solution {
+    pub fn group_anagrams(strs: Vec<String>) -> Vec<Vec<String>> {
+        let mut result = HashMap::with_capacity(strs.len());
+
+        for word in strs {
+            let mut characters = HashMap::with_capacity(26);
+
+            for c in word.chars() {
+                let entry = characters.entry(c).or_insert(0);
+                *entry += 1;
+            }
+
+            let state = WordState { characters };
+            dbg!(&state);
+            let entry = result.entry(state).or_insert(vec![]);
+            entry.push(word);
+        }
+
+        result.into_values().collect()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_49() {
+        assert_eq!(
+            WordState {
+                characters: HashMap::from([('e', 1), ('a', 1), ('t', 1)])
+            },
+            WordState {
+                characters: HashMap::from([('a', 1), ('t', 1), ('e', 1)])
+            }
+        );
+        assert_eq!(
+            vec![
+                vec!["bat".to_owned()],
+                vec!["nat".to_owned(), "tan".to_owned()],
+                vec!["ate".to_owned(), "eat".to_owned(), "tea".to_owned()]
+            ],
+            Solution::group_anagrams(vec![
+                "eat".to_owned(),
+                "tea".to_owned(),
+                "tan".to_owned(),
+                "ate".to_owned(),
+                "nat".to_owned(),
+                "bat".to_owned()
+            ])
+        );
+    }
+}