feat: Update the implementation of hash_map_open_addressing.js and .ts (#881)

* add permutations_ii.c and re-implement permutations_i.c

* Update the implementation of hash_map_open_addressing.js and .ts

* Update hash_map_open_addressing.js

* Update hash_map_open_addressing.js

codes/javascript/chapter_hashing/hash_map_open_addressing.js

@@ -1,7 +1,7 @@
 /**
- * File: hash_map_open_addressing.js
+ * File: hashMapOpenAddressing.js
- * Created Time: 2023-08-06
+ * Created Time: 2023-06-13
- * Author: yuan0221 (yl1452491917@gmail.com)
+ * Author: yuan0221 (yl1452491917@gmail.com), Krahets (krahets@163.com)
  */
 
 /* 键值对 Number -> String */
@@ -19,16 +19,16 @@ class HashMapOpenAddressing {
     #loadThres; // 触发扩容的负载因子阈值
     #extendRatio; // 扩容倍数
     #buckets; // 桶数组
-    #removed; // 删除标记
+    #TOMBSTONE; // 删除标记
 
     /* 构造方法 */
     constructor() {
-        this.#size = 0;
+        this.#size = 0; // 键值对数量
-        this.#capacity = 4;
+        this.#capacity = 4; // 哈希表容量
-        this.#loadThres = 2.0 / 3.0;
+        this.#loadThres = 2.0 / 3.0; // 触发扩容的负载因子阈值
-        this.#extendRatio = 2;
+        this.#extendRatio = 2; // 扩容倍数
-        this.#buckets = new Array(this.#capacity).fill(null);
+        this.#buckets = Array(this.#capacity).fill(null); // 桶数组
-        this.#removed = new Pair(-1, '-1');
+        this.#TOMBSTONE = new Pair(-1, '-1'); // 删除标记
     }
 
     /* 哈希函数 */
@@ -41,22 +41,48 @@ class HashMapOpenAddressing {
         return this.#size / this.#capacity;
     }
 
+    /* 搜索 key 对应的桶索引 */
+    #findBucket(key) {
+        let index = this.#hashFunc(key);
+        let firstTombstone = -1;
+        // 线性探测，当遇到空桶时跳出
+        while (this.#buckets[index] !== null) {
+            // 若遇到 key ，返回对应桶索引
+            if (this.#buckets[index].key === key) {
+                // 若之前遇到了删除标记，则将键值对移动至该索引
+                if (firstTombstone !== -1) {
+                    this.#buckets[firstTombstone] = this.#buckets[index];
+                    this.#buckets[index] = this.#TOMBSTONE;
+                    return firstTombstone; // 返回移动后的桶索引
+                }
+                return index; // 返回桶索引
+            }
+            // 记录遇到的首个删除标记
+            if (
+                firstTombstone === -1 &&
+                this.#buckets[index] === this.#TOMBSTONE
+            ) {
+                firstTombstone = index;
+            }
+            // 计算桶索引，越过尾部返回头部
+            index = (index + 1) % this.#capacity;
+        }
+        // 若 key 不存在，则返回添加点的索引
+        return firstTombstone === -1 ? index : firstTombstone;
+    }
+
     /* 查询操作 */
     get(key) {
-        const index = this.#hashFunc(key);
+        // 搜索 key 对应的桶索引
-        // 线性探测，从 index 开始向后遍历
+        const index = this.#findBucket(key);
-        for (let i = 0; i < this.#capacity; i++) {
+        // 若找到键值对，则返回对应 val
-            // 计算桶索引，越过尾部返回头部
-            const j = (index + i) % this.#capacity;
-            // 若遇到空桶，说明无此 key ，则返回 null
-            if (this.#buckets[j] === null) return null;
-            // 若遇到指定 key ，则返回对应 val
         if (
-                this.#buckets[j].key === key &&
+            this.#buckets[index] !== null &&
-                this.#buckets[j].key !== this.#removed.key
+            this.#buckets[index] !== this.#TOMBSTONE
-            )
+        ) {
-                return this.#buckets[j].val;
+            return this.#buckets[index].val;
         }
+        // 若键值对不存在，则返回 null
         return null;
     }
 
@@ -66,45 +92,32 @@ class HashMapOpenAddressing {
         if (this.#loadFactor() > this.#loadThres) {
             this.#extend();
         }
-        const index = this.#hashFunc(key);
+        // 搜索 key 对应的桶索引
-        // 线性探测，从 index 开始向后遍历
+        const index = this.#findBucket(key);
-        for (let i = 0; i < this.#capacity; i++) {
+        // 若找到键值对，则覆盖 val 并返回
-            // 计算桶索引，越过尾部返回头部
-            let j = (index + i) % this.#capacity;
-            // 若遇到空桶、或带有删除标记的桶，则将键值对放入该桶
         if (
-                this.#buckets[j] === null ||
+            this.#buckets[index] !== null &&
-                this.#buckets[j].key === this.#removed.key
+            this.#buckets[index] !== this.#TOMBSTONE
         ) {
-                this.#buckets[j] = new Pair(key, val);
+            this.#buckets[index].val = val;
-                this.#size += 1;
             return;
         }
-            // 若遇到指定 key ，则更新对应 val
+        // 若键值对不存在，则添加该键值对
-            if (this.#buckets[j].key === key) {
+        this.#buckets[index] = new Pair(key, val);
-                this.#buckets[j].val = val;
+        this.#size++;
-                return;
-            }
-        }
     }
 
     /* 删除操作 */
     remove(key) {
-        const index = this.#hashFunc(key);
+        // 搜索 key 对应的桶索引
-        // 线性探测，从 index 开始向后遍历
+        const index = this.#findBucket(key);
-        for (let i = 0; i < this.#capacity; i++) {
+        // 若找到键值对，则用删除标记覆盖它
-            // 计算桶索引，越过尾部返回头部
+        if (
-            const j = (index + i) % this.#capacity;
+            this.#buckets[index] !== null &&
-            // 若遇到空桶，说明无此 key ，则直接返回
+            this.#buckets[index] !== this.#TOMBSTONE
-            if (this.#buckets[j] === null) {
+        ) {
-                return;
+            this.#buckets[index] = this.#TOMBSTONE;
-            }
+            this.#size--;
-            // 若遇到指定 key ，则标记删除并返回
-            if (this.#buckets[j].key === key) {
-                this.#buckets[j] = this.#removed;
-                this.#size -= 1;
-                return;
-            }
         }
     }
 
@@ -114,11 +127,11 @@ class HashMapOpenAddressing {
         const bucketsTmp = this.#buckets;
         // 初始化扩容后的新哈希表
         this.#capacity *= this.#extendRatio;
-        this.#buckets = new Array(this.#capacity).fill(null);
+        this.#buckets = Array(this.#capacity).fill(null);
         this.#size = 0;
         // 将键值对从原哈希表搬运至新哈希表
         for (const pair of bucketsTmp) {
-            if (pair !== null && pair.key !== this.#removed.key) {
+            if (pair !== null && pair !== this.#TOMBSTONE) {
                 this.put(pair.key, pair.val);
             }
         }
@@ -127,36 +140,38 @@ class HashMapOpenAddressing {
     /* 打印哈希表 */
     print() {
         for (const pair of this.#buckets) {
-            if (pair !== null) {
+            if (pair === null) {
-                console.log(pair.key + ' -> ' + pair.val);
-            } else {
                 console.log('null');
+            } else if (pair === this.#TOMBSTONE) {
+                console.log('TOMBSTONE');
+            } else {
+                console.log(pair.key + ' -> ' + pair.val);
             }
         }
     }
 }
 
 /* Driver Code */
-/* 初始化哈希表 */
+// 初始化哈希表
-let map = new HashMapOpenAddressing();
+const hashmap = new HashMapOpenAddressing();
 
-/* 添加操作 */
+// 添加操作
-// 在哈希表中添加键值对 (key, value)
+// 在哈希表中添加键值对 (key, val)
-map.put(12836, '小哈');
+hashmap.put(12836, '小哈');
-map.put(15937, '小啰');
+hashmap.put(15937, '小啰');
-map.put(16750, '小算');
+hashmap.put(16750, '小算');
-map.put(13276, '小法');
+hashmap.put(13276, '小法');
-map.put(10583, '小鸭');
+hashmap.put(10583, '小鸭');
 console.log('\n添加完成后，哈希表为\nKey -> Value');
-map.print();
+hashmap.print();
 
-/* 查询操作 */
+// 查询操作
-// 向哈希表输入键 key ，得到值 value
+// 向哈希表输入键 key ，得到值 val
-const name = map.get(13276);
+const name = hashmap.get(13276);
 console.log('\n输入学号 13276 ，查询到姓名 ' + name);
 
-/* 删除操作 */
+// 删除操作
-// 在哈希表中删除键值对 (key, value)
+// 在哈希表中删除键值对 (key, val)
-map.remove(16750);
+hashmap.remove(16750);
 console.log('\n删除 16750 后，哈希表为\nKey -> Value');
-map.print();
+hashmap.print();

codes/typescript/chapter_hashing/hash_map_open_addressing.ts

@@ -1,13 +1,14 @@
 /**
  * File: hash_map_open_addressing.ts
  * Created Time: 2023-08-06
- * Author: yuan0221 (yl1452491917@gmail.com)
+ * Author: yuan0221 (yl1452491917@gmail.com), Krahets (krahets@163.com)
  */
 
 /* 键值对 Number -> String */
 class Pair {
     key: number;
     val: string;
+
     constructor(key: number, val: string) {
         this.key = key;
         this.val = val;
@@ -16,111 +17,124 @@ class Pair {
 
 /* 开放寻址哈希表 */
 class HashMapOpenAddressing {
-    #size: number; // 键值对数量
+    private size: number; // 键值对数量
-    #capacity: number; // 哈希表容量
+    private capacity: number; // 哈希表容量
-    #loadThres: number; // 触发扩容的负载因子阈值
+    private loadThres: number; // 触发扩容的负载因子阈值
-    #extendRatio: number; // 扩容倍数
+    private extendRatio: number; // 扩容倍数
-    #buckets: Pair[]; // 桶数组
+    private buckets: Array<Pair | null>; // 桶数组
-    #removed: Pair; // 删除标记
+    private TOMBSTONE: Pair; // 删除标记
 
     /* 构造方法 */
     constructor() {
-        this.#size = 0;
+        this.size = 0; // 键值对数量
-        this.#capacity = 4;
+        this.capacity = 4; // 哈希表容量
-        this.#loadThres = 2.0 / 3.0;
+        this.loadThres = 2.0 / 3.0; // 触发扩容的负载因子阈值
-        this.#extendRatio = 2;
+        this.extendRatio = 2; // 扩容倍数
-        this.#buckets = new Array(this.#capacity).fill(null);
+        this.buckets = Array(this.capacity).fill(null); // 桶数组
-        this.#removed = new Pair(-1, '-1');
+        this.TOMBSTONE = new Pair(-1, '-1'); // 删除标记
     }
 
     /* 哈希函数 */
-    #hashFunc(key: number): number {
+    private hashFunc(key: number): number {
-        return key % this.#capacity;
+        return key % this.capacity;
     }
 
     /* 负载因子 */
-    #loadFactor(): number {
+    private loadFactor(): number {
-        return this.#size / this.#capacity;
+        return this.size / this.capacity;
+    }
+
+    /* 搜索 key 对应的桶索引 */
+    private findBucket(key: number): number {
+        let index = this.hashFunc(key);
+        let firstTombstone = -1;
+        // 线性探测，当遇到空桶时跳出
+        while (this.buckets[index] !== null) {
+            // 若遇到 key ，返回对应桶索引
+            if (this.buckets[index]!.key === key) {
+                // 若之前遇到了删除标记，则将键值对移动至该索引
+                if (firstTombstone !== -1) {
+                    this.buckets[firstTombstone] = this.buckets[index];
+                    this.buckets[index] = this.TOMBSTONE;
+                    return firstTombstone; // 返回移动后的桶索引
+                }
+                return index; // 返回桶索引
+            }
+            // 记录遇到的首个删除标记
+            if (
+                firstTombstone === -1 &&
+                this.buckets[index] === this.TOMBSTONE
+            ) {
+                firstTombstone = index;
+            }
+            // 计算桶索引，越过尾部返回头部
+            index = (index + 1) % this.capacity;
+        }
+        // 若 key 不存在，则返回添加点的索引
+        return firstTombstone === -1 ? index : firstTombstone;
     }
 
     /* 查询操作 */
     get(key: number): string | null {
-        const index = this.#hashFunc(key);
+        // 搜索 key 对应的桶索引
-        // 线性探测，从 index 开始向后遍历
+        const index = this.findBucket(key);
-        for (let i = 0; i < this.#capacity; i++) {
+        // 若找到键值对，则返回对应 val
-            // 计算桶索引，越过尾部返回头部
-            const j = (index + i) % this.#capacity;
-            // 若遇到空桶，说明无此 key ，则返回 null
-            if (this.#buckets[j] === null) return null;
-            // 若遇到指定 key ，则返回对应 val
         if (
-                this.#buckets[j].key === key &&
+            this.buckets[index] !== null &&
-                this.#buckets[j].key !== this.#removed.key
+            this.buckets[index] !== this.TOMBSTONE
-            )
+        ) {
-                return this.#buckets[j].val;
+            return this.buckets[index]!.val;
         }
+        // 若键值对不存在，则返回 null
         return null;
     }
 
     /* 添加操作 */
     put(key: number, val: string): void {
         // 当负载因子超过阈值时，执行扩容
-        if (this.#loadFactor() > this.#loadThres) {
+        if (this.loadFactor() > this.loadThres) {
-            this.#extend();
+            this.extend();
         }
-        const index = this.#hashFunc(key);
+        // 搜索 key 对应的桶索引
-        // 线性探测，从 index 开始向后遍历
+        const index = this.findBucket(key);
-        for (let i = 0; i < this.#capacity; i++) {
+        // 若找到键值对，则覆盖 val 并返回
-            // 计算桶索引，越过尾部返回头部
-            let j = (index + i) % this.#capacity;
-            // 若遇到空桶、或带有删除标记的桶，则将键值对放入该桶
         if (
-                this.#buckets[j] === null ||
+            this.buckets[index] !== null &&
-                this.#buckets[j].key === this.#removed.key
+            this.buckets[index] !== this.TOMBSTONE
         ) {
-                this.#buckets[j] = new Pair(key, val);
+            this.buckets[index]!.val = val;
-                this.#size += 1;
             return;
         }
-            // 若遇到指定 key ，则更新对应 val
+        // 若键值对不存在，则添加该键值对
-            if (this.#buckets[j].key === key) {
+        this.buckets[index] = new Pair(key, val);
-                this.#buckets[j].val = val;
+        this.size++;
-                return;
-            }
-        }
     }
 
     /* 删除操作 */
     remove(key: number): void {
-        const index = this.#hashFunc(key);
+        // 搜索 key 对应的桶索引
-        // 线性探测，从 index 开始向后遍历
+        const index = this.findBucket(key);
-        for (let i = 0; i < this.#capacity; i++) {
+        // 若找到键值对，则用删除标记覆盖它
-            // 计算桶索引，越过尾部返回头部
+        if (
-            const j = (index + i) % this.#capacity;
+            this.buckets[index] !== null &&
-            // 若遇到空桶，说明无此 key ，则直接返回
+            this.buckets[index] !== this.TOMBSTONE
-            if (this.#buckets[j] === null) {
+        ) {
-                return;
+            this.buckets[index] = this.TOMBSTONE;
-            }
+            this.size--;
-            // 若遇到指定 key ，则标记删除并返回
-            if (this.#buckets[j].key === key) {
-                this.#buckets[j] = this.#removed;
-                this.#size -= 1;
-                return;
-            }
         }
     }
 
     /* 扩容哈希表 */
-    #extend(): void {
+    private extend(): void {
         // 暂存原哈希表
-        const bucketsTmp = this.#buckets;
+        const bucketsTmp = this.buckets;
         // 初始化扩容后的新哈希表
-        this.#capacity *= this.#extendRatio;
+        this.capacity *= this.extendRatio;
-        this.#buckets = new Array(this.#capacity).fill(null);
+        this.buckets = Array(this.capacity).fill(null);
-        this.#size = 0;
+        this.size = 0;
         // 将键值对从原哈希表搬运至新哈希表
         for (const pair of bucketsTmp) {
-            if (pair !== null && pair.key !== this.#removed.key) {
+            if (pair !== null && pair !== this.TOMBSTONE) {
                 this.put(pair.key, pair.val);
             }
         }
@@ -128,39 +142,41 @@ class HashMapOpenAddressing {
 
     /* 打印哈希表 */
     print(): void {
-        for (const pair of this.#buckets) {
+        for (const pair of this.buckets) {
-            if (pair !== null) {
+            if (pair === null) {
-                console.log(pair.key + ' -> ' + pair.val);
-            } else {
                 console.log('null');
+            } else if (pair === this.TOMBSTONE) {
+                console.log('TOMBSTONE');
+            } else {
+                console.log(pair.key + ' -> ' + pair.val);
             }
         }
     }
 }
 
 /* Driver Code */
-/* 初始化哈希表 */
+// 初始化哈希表
-let map = new HashMapOpenAddressing();
+const hashmap = new HashMapOpenAddressing();
 
-/* 添加操作 */
+// 添加操作
-// 在哈希表中添加键值对 (key, value)
+// 在哈希表中添加键值对 (key, val)
-map.put(12836, '小哈');
+hashmap.put(12836, '小哈');
-map.put(15937, '小啰');
+hashmap.put(15937, '小啰');
-map.put(16750, '小算');
+hashmap.put(16750, '小算');
-map.put(13276, '小法');
+hashmap.put(13276, '小法');
-map.put(10583, '小鸭');
+hashmap.put(10583, '小鸭');
 console.log('\n添加完成后，哈希表为\nKey -> Value');
-map.print();
+hashmap.print();
 
-/* 查询操作 */
+// 查询操作
-// 向哈希表输入键 key ，得到值 value
+// 向哈希表输入键 key ，得到值 val
-const name = map.get(13276);
+const name = hashmap.get(13276);
 console.log('\n输入学号 13276 ，查询到姓名 ' + name);
 
-/* 删除操作 */
+// 删除操作
-// 在哈希表中删除键值对 (key, value)
+// 在哈希表中删除键值对 (key, val)
-map.remove(16750);
+hashmap.remove(16750);
 console.log('\n删除 16750 后，哈希表为\nKey -> Value');
-map.print();
+hashmap.print();
 
 export {};