From 13bb76c283542693c418053db20ee65cd0050a7b Mon Sep 17 00:00:00 2001
From: WangSL <48207171+WSL0809@users.noreply.github.com>
Date: Wed, 26 Jul 2023 15:42:47 +0800
Subject: [PATCH] feat: add rust code for build_in_hash and hash_collision
 (#629)

* Create hash_map_chaining.rs

* Create hash_map_open_addressing.rs

* Create build_in_hash.rs

* Update Cargo.toml
---
 codes/rust/Cargo.toml                         |  17 +-
 codes/rust/chapter_hashing/build_in_hash.rs   |  50 +++++
 .../rust/chapter_hashing/hash_map_chaining.rs | 164 ++++++++++++++++
 .../hash_map_open_addressing.rs               | 181 ++++++++++++++++++
 4 files changed, 411 insertions(+), 1 deletion(-)
 create mode 100644 codes/rust/chapter_hashing/build_in_hash.rs
 create mode 100644 codes/rust/chapter_hashing/hash_map_chaining.rs
 create mode 100644 codes/rust/chapter_hashing/hash_map_open_addressing.rs

diff --git a/codes/rust/Cargo.toml b/codes/rust/Cargo.toml
index 12065cf8..1b311391 100644
--- a/codes/rust/Cargo.toml
+++ b/codes/rust/Cargo.toml
@@ -89,6 +89,21 @@ path = "chapter_hashing/hash_map.rs"
 name = "array_hash_map"
 path = "chapter_hashing/array_hash_map.rs"
 
+# Run Command: cargo run --bin build_in_hash
+[[bin]]
+name = "build_in_hash"
+path = "chapter_hashing/build_in_hash.rs"
+
+# Run Command: cargo run --bin hash_map_chaining
+[[bin]]
+name = "hash_map_chaining"
+path = "chapter_hashing/hash_map_chaining.rs"
+
+# Run Command: cargo run --bin hash_map_open_addressing
+[[bin]]
+name = "hash_map_open_addressing"
+path = "chapter_hashing/hash_map_open_addressing.rs"
+
 # Run Command: cargo run --bin binary_search
 [[bin]]
 name = "binary_search"
@@ -375,4 +390,4 @@ name = "max_product_cutting"
 path = "chapter_greedy/max_product_cutting.rs"
 
 [dependencies]
-rand = "0.8.5"
\ No newline at end of file
+rand = "0.8.5"
diff --git a/codes/rust/chapter_hashing/build_in_hash.rs b/codes/rust/chapter_hashing/build_in_hash.rs
new file mode 100644
index 00000000..7ea7620b
--- /dev/null
+++ b/codes/rust/chapter_hashing/build_in_hash.rs
@@ -0,0 +1,50 @@
+/*
+ * File: build_in_hash.rs
+ * Created Time: 2023-7-6
+ * Author: WSL0809 (wslzzy@outlook.com)
+ */
+
+include!("../include/include.rs");
+
+use crate::list_node::ListNode;
+use std::collections::hash_map::DefaultHasher;
+use std::hash::{Hash, Hasher};
+
+/* Driver Code */
+fn main() {
+    let num = 3;
+    let mut num_hasher = DefaultHasher::new();
+    num.hash(&mut num_hasher);
+    let hash_num = num_hasher.finish();
+    println!("整数 {} 的哈希值为 {}", num, hash_num);
+
+    let bol = true;
+    let mut bol_hasher = DefaultHasher::new();
+    bol.hash(&mut bol_hasher);
+    let hash_bol = bol_hasher.finish();
+    println!("布尔量 {} 的哈希值为 {}", bol, hash_bol);
+
+    let dec: f32 = 3.14159;
+    let mut dec_hasher = DefaultHasher::new();
+    dec.to_bits().hash(&mut dec_hasher);
+    let hash_dec = dec_hasher.finish();
+    println!("小数 {} 的哈希值为 {}", dec, hash_dec);
+
+    let str = "Hello 算法";
+    let mut str_hasher = DefaultHasher::new();
+    str.hash(&mut str_hasher);
+    let hash_str = str_hasher.finish();
+    println!("字符串 {} 的哈希值为 {}", str, hash_str);
+
+    let arr = (&12836, &"小哈");
+    let mut tup_hasher = DefaultHasher::new();
+    arr.hash(&mut tup_hasher);
+    let hash_tup = tup_hasher.finish();
+    println!("元组 {:?} 的哈希值为 {}", arr, hash_tup);
+
+    let node = ListNode::new(42);
+    let mut hasher = DefaultHasher::new();
+    node.borrow().val.hash(&mut hasher);
+    let hash = hasher.finish();
+    println!("节点对象 {:?} 的哈希值为{}", node, hash);
+}
diff --git a/codes/rust/chapter_hashing/hash_map_chaining.rs b/codes/rust/chapter_hashing/hash_map_chaining.rs
new file mode 100644
index 00000000..93e84c49
--- /dev/null
+++ b/codes/rust/chapter_hashing/hash_map_chaining.rs
@@ -0,0 +1,164 @@
+/*
+ * File: hash_map_chaining.rs
+ * Created Time: 2023-07-07
+ * Author: WSL0809 (wslzzy@outlook.com)
+ */
+
+#[derive(Clone)]
+/* 键值对 */
+struct Pair {
+    key: i32,
+    val: String,
+}
+
+/* 链式地址哈希表 */
+struct HashMapChaining {
+    size: i32,
+    capacity: i32,
+    load_thres: f32,
+    extend_ratio: i32,
+    buckets: Vec<Vec<Pair>>,
+}
+
+impl HashMapChaining {
+    /* 构造方法 */
+    fn new() -> Self {
+        Self {
+            size: 0,
+            capacity: 4,
+            load_thres: 2.0 / 3.0,
+            extend_ratio: 2,
+            buckets: vec![vec![]; 4],
+        }
+    }
+
+    /* 哈希函数 */
+    fn hash_func(&self, key: i32) -> usize {
+        key as usize % self.capacity as usize
+    }
+
+    /* 负载因子 */
+    fn load_factor(&self) -> f32 {
+        self.size as f32 / self.capacity as f32
+    }
+
+    /* 删除操作 */
+    fn remove(&mut self, key: i32) -> Option<String> {
+        let index = self.hash_func(key);
+        let bucket = &mut self.buckets[index];
+
+        // 遍历桶，从中删除键值对
+        for i in 0..bucket.len() {
+            if bucket[i].key == key {
+                let pair = bucket.remove(i);
+                self.size -= 1;
+                return Some(pair.val);
+            }
+        }
+
+        // 若未找到 key 则返回 None
+        None
+    }
+
+    /* 扩容哈希表 */
+    fn extend(&mut self) {
+        // 暂存原哈希表
+        let buckets_tmp = std::mem::replace(&mut self.buckets, vec![]);
+
+        // 初始化扩容后的新哈希表
+        self.capacity *= self.extend_ratio;
+        self.buckets = vec![Vec::new(); self.capacity as usize];
+        self.size = 0;
+
+        // 将键值对从原哈希表搬运至新哈希表
+        for bucket in buckets_tmp {
+            for pair in bucket {
+                self.put(pair.key, pair.val);
+            }
+        }
+    }
+
+    /* 打印哈希表 */
+    fn print(&self) {
+        for bucket in &self.buckets {
+            let mut res = Vec::new();
+            for pair in bucket {
+                res.push(format!("{} -> {}", pair.key, pair.val));
+            }
+            println!("{:?}", res);
+        }
+    }
+
+    /* 添加操作 */
+    fn put(&mut self, key: i32, val: String) {
+        // 当负载因子超过阈值时，执行扩容
+        if self.load_factor() > self.load_thres {
+            self.extend();
+        }
+
+        let index = self.hash_func(key);
+        let bucket = &mut self.buckets[index];
+
+        // 遍历桶，若遇到指定 key ，则更新对应 val 并返回
+        for pair in bucket {
+            if pair.key == key {
+                pair.val = val.clone();
+                return;
+            }
+        }
+        let bucket = &mut self.buckets[index];
+
+        // 若无该 key ，则将键值对添加至尾部
+        let pair = Pair {
+            key,
+            val: val.clone(),
+        };
+        bucket.push(pair);
+        self.size += 1;
+    }
+
+    /* 查询操作 */
+    fn get(&self, key: i32) -> Option<&str> {
+        let index = self.hash_func(key);
+        let bucket = &self.buckets[index];
+
+        // 遍历桶，若找到 key 则返回对应 val
+        for pair in bucket {
+            if pair.key == key {
+                return Some(&pair.val);
+            }
+        }
+
+        // 若未找到 key 则返回 None
+        None
+    }
+}
+
+/* Driver Code */
+pub fn main() {
+    /* 初始化哈希表 */
+    let mut map = HashMapChaining::new();
+
+    /* 添加操作 */
+    // 在哈希表中添加键值对 (key, value)
+    map.put(12836, "小哈".to_string());
+    map.put(15937, "小啰".to_string());
+    map.put(16750, "小算".to_string());
+    map.put(13276, "小法".to_string());
+    map.put(10583, "小鸭".to_string());
+    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
+    println!("\n输入学号 13276,查询到姓名 {}", match map.get(13276) {
+        Some(value) => value,
+        None => "Not a valid Key"
+    });
+
+    /* 删除操作 */
+    // 在哈希表中删除键值对 (key, value)
+    map.remove(12836);
+    println!("\n删除 12836 后，哈希表为\nKey -> Value");
+    map.print();
+}
diff --git a/codes/rust/chapter_hashing/hash_map_open_addressing.rs b/codes/rust/chapter_hashing/hash_map_open_addressing.rs
new file mode 100644
index 00000000..0be96e61
--- /dev/null
+++ b/codes/rust/chapter_hashing/hash_map_open_addressing.rs
@@ -0,0 +1,181 @@
+/*
+ * File: hash_map_open_addressing.rs
+ * Created Time: 2023-07-16
+ * Author: WSL0809 (wslzzy@outlook.com)
+ */
+
+#[derive(Clone, PartialEq)]
+/* 键值对 */
+struct Pair {
+    key: i32,
+    val: String,
+}
+
+/* 开放寻址哈希表 */
+struct HashMapOpenAddressing {
+    size: usize,
+    capacity: usize,
+    load_thres: f32,
+    extend_ratio: usize,
+    buckets: Vec<Option<Pair>>,
+    removed: Pair,
+}
+
+
+impl HashMapOpenAddressing {
+    /* 构造方法 */
+    fn new() -> Self {
+        Self {
+            size: 0,
+            capacity: 4,
+            load_thres: 2.0 / 3.0,
+            extend_ratio: 2,
+            buckets: vec![None; 4],
+            removed: Pair {
+                key: -1,
+                val: "-1".to_string(),
+            },
+        }
+    }
+
+    /* 哈希函数 */
+    fn hash_func(&self, key: i32) -> usize {
+        (key % self.capacity as i32) as usize
+    }
+
+    /* 负载因子 */
+    fn load_factor(&self) -> f32 {
+        self.size as f32 / self.capacity as f32
+    }
+
+    /* 查询操作 */
+    fn get(&self, key: i32) -> Option<&str> {
+        let mut index = self.hash_func(key);
+        let capacity = self.capacity;
+        // 线性探测，从 index 开始向后遍历
+        for _ in 0..capacity {
+            // 计算桶索引，越过尾部返回头部
+            let j = (index + 1) % capacity;
+            match &self.buckets[j] {
+                // 若遇到空桶，说明无此 key ，则返回 None
+                None => return None,
+                // 若遇到指定 key ，则返回对应 val
+                Some(pair) if pair.key == key && pair != &self.removed => return Some(&pair.val),
+                _ => index = j,
+            }
+        }
+
+        None
+    }
+
+    /* 添加操作 */
+    fn put(&mut self, key: i32, val: String) {
+        // 当负载因子超过阈值时，执行扩容
+        if self.load_factor() > self.load_thres {
+            self.extend();
+        }
+
+        let mut index = self.hash_func(key);
+        let capacity = self.capacity;
+
+        // 线性探测，从 index 开始向后遍历
+        for _ in 0..capacity {
+            //计算桶索引，越过尾部返回头部
+            let j = (index + 1) % capacity;
+            // 若遇到空桶、或带有删除标记的桶，则将键值对放入该桶
+            match &mut self.buckets[j] {
+                bucket @ &mut None | bucket @ &mut Some(Pair { key: -1, .. }) => {
+                    *bucket = Some(Pair { key, val });
+                    self.size += 1;
+                    return;
+                }
+                // 若遇到指定 key ，则更新对应 val
+                Some(pair) if pair.key == key => {
+                    pair.val = val;
+                    return;
+                }
+                _ => index = j,
+            }
+        }
+    }
+
+    /* 删除操作 */
+    fn remove(&mut self, key: i32) {
+        let mut index = self.hash_func(key);
+        let capacity = self.capacity;
+
+        // 遍历桶，从中删除键值对
+        for _ in 0..capacity {
+            let j = (index + 1) % capacity;
+            match &mut self.buckets[j] {
+                // 若遇到空桶，说明无此 key ，则直接返回
+                None => return,
+                // 若遇到指定 key ，则标记删除并返回
+                Some(pair) if pair.key == key => {
+                    *pair = Pair {
+                        key: -1,
+                        val: "-1".to_string(),
+                    };
+                    self.size -= 1;
+                    return;
+                }
+                _ => index = j,
+            }
+        }
+    }
+
+
+    /* 扩容哈希表 */
+    fn extend(&mut self) {
+        // 暂存原哈希表
+        let buckets_tmp = self.buckets.clone();
+        // 初始化扩容后的新哈希表
+        self.capacity *= self.extend_ratio;
+        self.buckets = vec![None; self.capacity];
+        self.size = 0;
+
+        // 将键值对从原哈希表搬运至新哈希表
+        for pair in buckets_tmp {
+            if let Some(pair) = pair {
+                self.put(pair.key, pair.val);
+            }
+        }
+    }
+    /* 打印哈希表 */
+    fn print(&self) {
+        for pair in &self.buckets {
+            match pair {
+                Some(pair) => println!("{} -> {}", pair.key, pair.val),
+                None => println!("None"),
+            }
+        }
+    }
+}
+
+/* Driver Code */
+fn main() {
+    /* 初始化哈希表 */
+    let mut hashmap = HashMapOpenAddressing::new();
+
+    /* 添加操作 */
+    // 在哈希表中添加键值对 (key, value)
+    hashmap.put(12836, "小哈".to_string());
+    hashmap.put(15937, "小啰".to_string());
+    hashmap.put(16750, "小算".to_string());
+    hashmap.put(13276, "小法".to_string());
+    hashmap.put(10583, "小鸭".to_string());
+
+    println!("\n添加完成后,哈希表为\nKey -> Value");
+    hashmap.print();
+
+    /* 查询操作 */
+    // 向哈希表输入键 key ，得到值 value
+    let name = hashmap.get(13276).unwrap();
+    println!("\n输入学号 13276 ,查询到姓名 {}", name);
+
+    /* 删除操作 */
+    // 在哈希表中删除键值对 (key, value)
+    hashmap.remove(16750);
+    println!("\n删除 16750 后,哈希表为\nKey -> Value");
+    hashmap.print();
+}