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hello-algo/codes/rust/chapter_hashing/array_hash_map.rs

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/**
* File: array_hash_map.rs
* Created Time: 2023-2-18
* Author: xBLACICEx (xBLACKICEx@outlook.com)
*/
#[derive(Debug, Clone)]
/* 键值对 */
pub struct Pair {
pub key: i32,
pub val: String,
}
/* 基于数组简易实现的哈希表 */
pub struct ArrayHashMap { buckets: Vec<Option<Pair>> }
impl ArrayHashMap {
pub fn new() -> ArrayHashMap {
// 初始化数组,包含 100 个桶
Self { buckets: vec![None; 100] }
}
/* 哈希函数 */
fn hash_func(&self, key: i32) -> usize {
key as usize % 100
}
/* 查询操作 */
pub fn get(&self, key: i32) -> Option<&String> {
let index = self.hash_func(key);
self.buckets[index].as_ref().map(|pair| &pair.val)
}
/* 添加操作 */
pub fn put(&mut self, key: i32, val: &str) {
let index = self.hash_func(key);
self.buckets[index] = Some(Pair {
key,
val: val.to_string(),
});
}
/* 删除操作 */
pub fn remove(&mut self, key: i32) {
let index = self.hash_func(key);
self.buckets[index] = None;
}
/* 获取所有键值对 */
pub fn entry_set(&self) -> Vec<&Pair> {
self.buckets.iter().filter_map(|pair| pair.as_ref()).collect()
}
/* 获取所有键 */
pub fn key_set(&self) -> Vec<&i32> {
self.buckets.iter().filter_map(|pair| pair.as_ref().map(|pair| &pair.key)).collect()
}
/* 获取所有值 */
pub fn value_set(&self) -> Vec<&String> {
self.buckets.iter().filter_map(|pair| pair.as_ref().map(|pair| &pair.val)).collect()
}
/* 打印哈希表 */
pub fn print(&self) {
for pair in self.entry_set() {
println!("{} -> {}", pair.key, pair.val);
}
}
}
fn main() {
/* 初始化哈希表 */
let mut map = ArrayHashMap::new();
/*添加操作 */
// 在哈希表中添加键值对key, value
map.put(12836, "小哈");
map.put(15937, "小啰");
map.put(16750, "小算");
map.put(13276, "小法");
map.put(10583, "小鸭");
println!("\n添加完成后哈希表为\nKey -> Value");
map.print();
/* 查询操作 */
// 向哈希表输入键 key ,得到值 value
let name = map.get(15937).unwrap();
println!("\n输入学号 15937 ,查询到姓名 {}", name);
/* 删除操作 */
// 在哈希表中删除键值对 (key, value)
map.remove(10583);
println!("\n删除 10583 后,哈希表为\nKey -> Value");
map.print();
/* 遍历哈希表 */
println!("\n遍历键值对 Key->Value");
for pair in map.entry_set() {
println!("{} -> {}", pair.key, pair.val);
}
println!("\n单独遍历键 Key");
for key in map.key_set() {
println!("{}", key);
}
println!("\n单独遍历值 Value");
for val in map.value_set() {
println!("{}", val);
}
}