✨ feat(rust/hashing): add array_hash_map (#373)

* ✨ feat(rust/hashing): add array_hash_map

* 📃 docs(rust/hashing): correct comments

codes/rust/Cargo.toml

@@ -49,6 +49,11 @@ path = "chapter_stack_and_queue/deque.rs"
 name = "hash_map"
 path = "chapter_hashing/hash_map.rs"
 
+# Run Command: cargo run --bin array_hash_map
+[[bin]]
+name = "array_hash_map"
+path = "chapter_hashing/array_hash_map.rs"
+
 # Run Command: cargo run --bin binary_search
 [[bin]]
 name = "binary_search"

codes/rust/chapter_hashing/array_hash_map.rs

@@ -0,0 +1,111 @@
+/**
+ * File: array_hash_map.rs
+ * Created Time: 2023-2-18
+ * Author: xBLACICEx (xBLACKICEx@outlook.com)
+ */
+
+#[derive(Debug, Clone)]
+/* 键值对 int->String */
+pub struct Entry {
+    pub key: i32,
+    pub val: String,
+}
+
+/* 基于数组简易实现的哈希表 */
+pub struct ArrayHashMap { bucket: Vec<Option<Entry>> }
+
+impl ArrayHashMap {
+    pub fn new() -> ArrayHashMap {
+        // 初始化一个长度为 100 的桶（数组）
+        Self { bucket: 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.bucket[index].as_ref().map(|entry| &entry.val)
+    }
+
+    /* 添加操作 */
+    pub fn put(&mut self, key: i32, val: &str) {
+        let index = self.hash_func(key);
+        self.bucket[index] = Some(Entry {
+            key,
+            val: val.to_string(),
+        });
+    }
+
+    /* 删除操作 */
+    pub fn remove(&mut self, key: i32) {
+        let index = self.hash_func(key);
+        self.bucket[index] = None;
+    }
+
+    /* 获取所有键值对 */
+    pub fn entry_set(&self) -> Vec<&Entry> {
+        self.bucket.iter().filter_map(|entry| entry.as_ref()).collect()
+    }
+
+    /* 获取所有键 */
+    pub fn key_set(&self) -> Vec<&i32> {
+        self.bucket.iter().filter_map(|entry| entry.as_ref().map(|entry| &entry.key)).collect()
+    }
+
+    /* 获取所有值 */
+    pub fn value_set(&self) -> Vec<&String> {
+        self.bucket.iter().filter_map(|entry| entry.as_ref().map(|entry| &entry.val)).collect()
+    }
+
+    /* 打印哈希表 */
+    pub fn print(&self) {
+        for entry in self.entry_set() {
+            println!("{} -> {}", entry.key, entry.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 entry in map.entry_set() {
+        println!("{} -> {}", entry.key, entry.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);
+    }
+}