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| use std::hash::{ Hasher, Hash }; | |
| use std::collections::{LinkedList, hash_map::DefaultHasher}; | |
| fn hash<K>(k: K) -> usize where K: Hash{ | |
| let mut hasher = DefaultHasher::new(); | |
| k.hash(&mut hasher); | |
| hasher.finish() as usize | |
| } | |
| struct HashMap<K, V> { | |
| store: Box<[LinkedList<(K, V, bool)>]>, | |
| size: usize, | |
| } | |
| impl<K, V> HashMap<K, V> where K: Clone + Hash + Eq, V: Clone { | |
| pub fn new(n: usize) -> Self { | |
| let mut store = Vec::new(); | |
| store.resize(n, LinkedList::<(K, V, bool)>::new()); | |
| Self { | |
| store: store.into_boxed_slice(), | |
| size: n, | |
| } | |
| } | |
| pub fn insert(&mut self, k: K, v: V) { | |
| let idx = hash(k.clone()); | |
| let state = self.store.get_mut(idx % self.size).unwrap(); | |
| let mut added = false; | |
| for item in state.iter_mut() { | |
| if !item.2 { | |
| if !added { | |
| item.0 = k.clone(); | |
| item.1 = v.clone(); | |
| item.2 = true; | |
| added = true; | |
| } | |
| } else if item.0 == k { | |
| if added { | |
| item.2 = false | |
| } else { | |
| item.1 = v.clone(); | |
| item.2 = true; | |
| added = true | |
| } | |
| } | |
| } | |
| if !added { | |
| state.push_back((k, v, true)); | |
| } | |
| } | |
| pub fn get(&self, k: K) -> Option<V>{ | |
| let idx = hash(k.clone()); | |
| let state = self.store.get(idx % self.size).unwrap(); | |
| for item in state.iter() { | |
| if item.2 && item.0 == k { | |
| return Some(item.1.clone()) | |
| } | |
| } | |
| None | |
| } | |
| pub fn get_mut(&mut self, k: K) -> Option<&mut V>{ | |
| let idx = hash(k.clone()); | |
| let state = self.store.get_mut(idx % self.size).unwrap(); | |
| for item in state.iter() { | |
| if item.2 && item.0 == k { | |
| return Some(&mut item.1) | |
| } | |
| } | |
| None | |
| } | |
| pub fn clear(&mut self) { | |
| for state in self.store.iter_mut() { | |
| state.clear(); | |
| } | |
| } | |
| pub fn len(&self) -> usize { | |
| let mut size = 0; | |
| for state in self.store.iter() { | |
| for item in state.iter() { | |
| if item.2 { | |
| size += 1; | |
| } | |
| } | |
| } | |
| size | |
| } | |
| pub fn iter(&self) -> HashMapIterator<'_, K, V> { | |
| HashMapIterator::new(self) | |
| } | |
| pub fn iter_mut(&mut self) -> HashMapIteratorMut<'_, K, V> { | |
| HashMapIteratorMut::new(self) | |
| } | |
| } | |
| struct HashMapIterator<'a, K, V> { | |
| map: &'a HashMap<K, V>, | |
| i: usize, | |
| j: usize, | |
| } | |
| impl<'a, K, V> HashMapIterator<'a, K, V> { | |
| pub fn new(map: &'a HashMap<K, V>) -> Self { | |
| Self { | |
| map: map, | |
| i: 0, | |
| j: 0, | |
| } | |
| } | |
| } | |
| impl<'a, K: Clone + Eq + Hash, V> Iterator for HashMapIterator<'a, K, V> { | |
| type Item = (&'a K, &'a V); | |
| fn next(&mut self) -> Option<Self::Item> { | |
| loop { | |
| if self.i >= self.map.store.len() { | |
| return None; | |
| } | |
| let state = self.map.store.get(self.i).unwrap(); | |
| let mut k = 0; | |
| for item in state.iter() { | |
| if k == self.j && item.2 { | |
| self.j+=1; | |
| return Some((&item.0, &item.1)) | |
| } | |
| k+=1; | |
| } | |
| self.j = 0; | |
| self.i+=1; | |
| } | |
| } | |
| } | |
| struct HashMapIteratorMut<'a, K, V> { | |
| map: &'a mut HashMap<K, V>, | |
| i: usize, | |
| j: usize, | |
| } | |
| impl<'a, K, V> HashMapIteratorMut<'a, K, V> { | |
| pub fn new(map: &'a mut HashMap<K, V>) -> Self { | |
| Self { | |
| map: map, | |
| i: 0, | |
| j: 0, | |
| } | |
| } | |
| } | |
| impl<'a, K: Clone + Eq + Hash, V: Clone> Iterator for HashMapIteratorMut<'a, K, V> { | |
| type Item = (K, &'a mut V); | |
| fn next(&mut self) -> Option<Self::Item> { | |
| let mut key: Option<K>; | |
| 'outer: loop { | |
| if self.i >= self.map.store.len() { | |
| return None; | |
| } | |
| let state = self.map.store.get_mut(self.i).unwrap(); | |
| let mut k = 0; | |
| for item in state.iter_mut() { | |
| if k == self.j && item.2 { | |
| self.j+=1; | |
| key = Some(item.0.clone()); | |
| break 'outer | |
| } | |
| k+=1; | |
| } | |
| self.j = 0; | |
| self.i+=1; | |
| } | |
| // FIXME | |
| key.map(|x| (x, self.map.get_mut(x).unwrap())) | |
| } | |
| } | |
| fn main() { | |
| let mut a = LinkedList::new(); | |
| a.push_back(3); | |
| let mut b = a.clone(); | |
| b.push_back(4); | |
| println!("Hello, world! {:?}", (a, b)); | |
| } | |
| #[cfg(test)] | |
| mod tests { | |
| use super::*; | |
| #[test] | |
| fn test_hashmap() { | |
| let mut m = HashMap::<&str, isize>::new(10); | |
| assert_eq!(m.len(), 0); | |
| m.insert("Hi", 1); | |
| m.insert("Hello", 2); | |
| assert_eq!(m.len(), 2); | |
| assert_eq!(m.get("Hi"), Some(1)); | |
| assert_eq!(m.get("Hello"), Some(2)); | |
| m.insert("Hi", 3); | |
| assert_eq!(m.get("Hi"), Some(3)); | |
| for (k, v) in m.iter() { | |
| println!("{:?}:{:?}", k, v); | |
| } | |
| m.clear(); | |
| assert_eq!(m.len(), 0); | |
| // assert!(false); | |
| } | |
| } | |
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