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krahets
2023-06-26 23:13:42 +08:00
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commit ce6ce9b444
5 changed files with 291 additions and 109 deletions
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chapter_hashing/hash_algorithm.md
+58 -4
View File
@@ -265,13 +265,45 @@ index = hash(key) % capacity
=== "C#"
```csharp title="simple_hash.cs"
[class]{simple_hash}-[func]{addHash}
/* 加法哈希 */
int addHash(string key) {
long hash = 0;
const int MODULUS = 1000000007;
foreach (char c in key) {
hash = (hash + c) % MODULUS;
}
return (int)hash;
}
[class]{simple_hash}-[func]{mulHash}
/* 乘法哈希 */
int mulHash(string key) {
long hash = 0;
const int MODULUS = 1000000007;
foreach (char c in key) {
hash = (31 * hash + c) % MODULUS;
}
return (int)hash;
}
[class]{simple_hash}-[func]{xorHash}
/* 异或哈希 */
int xorHash(string key) {
int hash = 0;
const int MODULUS = 1000000007;
foreach (char c in key) {
hash ^= c;
}
return hash & MODULUS;
}
[class]{simple_hash}-[func]{rotHash}
/* 旋转哈希 */
int rotHash(string key) {
long hash = 0;
const int MODULUS = 1000000007;
foreach (char c in key) {
hash = ((hash << 4) ^ (hash >> 28) ^ c) % MODULUS;
}
return (int)hash;
}
```
=== "Swift"
@@ -473,7 +505,29 @@ $$
=== "C#"
```csharp title="built_in_hash.cs"
int num = 3;
int hashNum = num.GetHashCode();
// 整数 3 的哈希值为 3;
bool bol = true;
int hashBol = bol.GetHashCode();
// 布尔量 true 的哈希值为 1;
double dec = 3.14159;
int hashDec = dec.GetHashCode();
// 小数 3.14159 的哈希值为 -1340954729;
string str = "Hello 算法";
int hashStr = str.GetHashCode();
// 字符串 Hello 算法 的哈希值为 -586107568;
object[] arr = { 12836, "小哈" };
int hashTup = arr.GetHashCode();
// 数组 [12836, 小哈] 的哈希值为 42931033;
ListNode obj = new ListNode(0);
int hashObj = obj.GetHashCode();
// 节点对象 0 的哈希值为 39053774;
```
=== "Swift"
chapter_hashing/hash_collision.md
+222 -98
View File
@@ -40,17 +40,6 @@ comments: true
=== "Java"
```java title="hash_map_chaining.java"
/* 键值对 */
class Pair {
public int key;
public String val;
public Pair(int key, String val) {
this.key = key;
this.val = val;
}
}
/* 链式地址哈希表 */
class HashMapChaining {
int size; // 键值对数量
@@ -163,17 +152,6 @@ comments: true
=== "C++"
```cpp title="hash_map_chaining.cpp"
/* 键值对 */
struct Pair {
public:
int key;
string val;
Pair(int key, string val) {
this->key = key;
this->val = val;
}
};
/* 链式地址哈希表 */
class HashMapChaining {
private:
@@ -280,13 +258,6 @@ comments: true
=== "Python"
```python title="hash_map_chaining.py"
class Pair:
"""键值对"""
def __init__(self, key: int, val: str):
self.key = key
self.val = val
class HashMapChaining:
"""链式地址哈希表"""
@@ -370,8 +341,6 @@ comments: true
=== "Go"
```go title="hash_map_chaining.go"
[class]{pair}-[func]{}
/* 链式地址哈希表 */
type hashMapChaining struct {
size int // 键值对数量
@@ -499,61 +468,147 @@ comments: true
=== "JavaScript"
```javascript title="hash_map_chaining.js"
[class]{Pair}-[func]{}
[class]{HashMapChaining}-[func]{}
```
=== "TypeScript"
```typescript title="hash_map_chaining.ts"
[class]{Pair}-[func]{}
[class]{HashMapChaining}-[func]{}
```
=== "C"
```c title="hash_map_chaining.c"
[class]{pair}-[func]{}
[class]{hashMapChaining}-[func]{}
```
=== "C#"
```csharp title="hash_map_chaining.cs"
[class]{Pair}-[func]{}
/* 链式地址哈希表 */
class HashMapChaining {
int size; // 键值对数量
int capacity; // 哈希表容量
double loadThres; // 触发扩容的负载因子阈值
int extendRatio; // 扩容倍数
List<List<Pair>> buckets; // 桶数组
[class]{HashMapChaining}-[func]{}
/* 构造方法 */
public HashMapChaining() {
size = 0;
capacity = 4;
loadThres = 2 / 3.0;
extendRatio = 2;
buckets = new List<List<Pair>>(capacity);
for (int i = 0; i < capacity; i++) {
buckets.Add(new List<Pair>());
}
}
/* 哈希函数 */
private int hashFunc(int key) {
return key % capacity;
}
/* 负载因子 */
private double loadFactor() {
return (double)size / capacity;
}
/* 查询操作 */
public string get(int key) {
int index = hashFunc(key);
// 遍历桶，若找到 key 则返回对应 val
foreach (Pair pair in buckets[index]) {
if (pair.key == key) {
return pair.val;
}
}
// 若未找到 key 则返回 null
return null;
}
/* 添加操作 */
public void put(int key, string val) {
// 当负载因子超过阈值时，执行扩容
if (loadFactor() > loadThres) {
extend();
}
int index = hashFunc(key);
// 遍历桶，若遇到指定 key ，则更新对应 val 并返回
foreach (Pair pair in buckets[index]) {
if (pair.key == key) {
pair.val = val;
return;
}
}
// 若无该 key ，则将键值对添加至尾部
buckets[index].Add(new Pair(key, val));
size++;
}
/* 删除操作 */
public void remove(int key) {
int index = hashFunc(key);
// 遍历桶，从中删除键值对
foreach (Pair pair in buckets[index].ToList()) {
if (pair.key == key) {
buckets[index].Remove(pair);
}
}
size--;
}
/* 扩容哈希表 */
private void extend() {
// 暂存原哈希表
List<List<Pair>> bucketsTmp = buckets;
// 初始化扩容后的新哈希表
capacity *= extendRatio;
buckets = new List<List<Pair>>(capacity);
for (int i = 0; i < capacity; i++) {
buckets.Add(new List<Pair>());
}
size = 0;
// 将键值对从原哈希表搬运至新哈希表
foreach (List<Pair> bucket in bucketsTmp) {
foreach (Pair pair in bucket) {
put(pair.key, pair.val);
}
}
}
/* 打印哈希表 */
public void print() {
foreach (List<Pair> bucket in buckets) {
List<string> res = new List<string>();
foreach (Pair pair in bucket) {
res.Add(pair.key + " -> " + pair.val);
}
foreach (string kv in res) {
Console.WriteLine(kv);
}
}
}
}
```
=== "Swift"
```swift title="hash_map_chaining.swift"
[class]{Pair}-[func]{}
[class]{HashMapChaining}-[func]{}
```
=== "Zig"
```zig title="hash_map_chaining.zig"
[class]{Pair}-[func]{}
[class]{HashMapChaining}-[func]{}
```
=== "Dart"
```dart title="hash_map_chaining.dart"
/* 键值对 */
class Pair {
int key;
String val;
Pair(this.key, this.val);
}
/* 链式地址哈希表 */
class HashMapChaining {
late int size; // 键值对数量
@@ -687,17 +742,6 @@ comments: true
=== "Java"
```java title="hash_map_open_addressing.java"
/* 键值对 */
class Pair {
public int key;
public String val;
public Pair(int key, String val) {
this.key = key;
this.val = val;
}
}
/* 开放寻址哈希表 */
class HashMapOpenAddressing {
private int size; // 键值对数量
@@ -821,15 +865,6 @@ comments: true
=== "C++"
```cpp title="hash_map_open_addressing.cpp"
/* 键值对 */
struct Pair {
int key;
string val;
Pair(int k, string v) : key(k), val(v) {
}
};
/* 开放寻址哈希表 */
class HashMapOpenAddressing {
private:
@@ -955,13 +990,6 @@ comments: true
=== "Python"
```python title="hash_map_open_addressing.py"
class Pair:
"""键值对"""
def __init__(self, key: int, val: str):
self.key = key
self.val = val
class HashMapOpenAddressing:
"""开放寻址哈希表"""
@@ -1057,8 +1085,6 @@ comments: true
=== "Go"
```go title="hash_map_open_addressing.go"
[class]{pair}-[func]{}
/* 链式地址哈希表 */
type hashMapOpenAddressing struct {
size int // 键值对数量
@@ -1195,61 +1221,159 @@ comments: true
=== "JavaScript"
```javascript title="hash_map_open_addressing.js"
[class]{Pair}-[func]{}
[class]{HashMapOpenAddressing}-[func]{}
```
=== "TypeScript"
```typescript title="hash_map_open_addressing.ts"
[class]{Pair}-[func]{}
[class]{HashMapOpenAddressing}-[func]{}
```
=== "C"
```c title="hash_map_open_addressing.c"
[class]{pair}-[func]{}
[class]{hashMapOpenAddressing}-[func]{}
```
=== "C#"
```csharp title="hash_map_open_addressing.cs"
[class]{Pair}-[func]{}
/* 开放寻址哈希表 */
class HashMapOpenAddressing {
int size; // 键值对数量
int capacity; // 哈希表容量
double loadThres; // 触发扩容的负载因子阈值
int extendRatio; // 扩容倍数
Pair[] buckets; // 桶数组
Pair removed; // 删除标记
[class]{HashMapOpenAddressing}-[func]{}
/* 构造方法 */
public HashMapOpenAddressing() {
size = 0;
capacity = 4;
loadThres = 2.0 / 3.0;
extendRatio = 2;
buckets = new Pair[capacity];
removed = new Pair(-1, "-1");
}
/* 哈希函数 */
private int hashFunc(int key) {
return key % capacity;
}
/* 负载因子 */
private double loadFactor() {
return (double)size / capacity;
}
/* 查询操作 */
public string get(int key) {
int index = hashFunc(key);
// 线性探测，从 index 开始向后遍历
for (int i = 0; i < capacity; i++) {
// 计算桶索引，越过尾部返回头部
int j = (index + i) % capacity;
// 若遇到空桶，说明无此 key ，则返回 null
if (buckets[j] == null)
return null;
// 若遇到指定 key ，则返回对应 val
if (buckets[j].key == key && buckets[j] != removed)
return buckets[j].val;
}
return null;
}
/* 添加操作 */
public void put(int key, string val) {
// 当负载因子超过阈值时，执行扩容
if (loadFactor() > loadThres) {
extend();
}
int index = hashFunc(key);
// 线性探测，从 index 开始向后遍历
for (int i = 0; i < capacity; i++) {
// 计算桶索引，越过尾部返回头部
int j = (index + i) % 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 (buckets[j] == null || buckets[j] == removed) {
buckets[j] = new Pair(key, val);
size += 1;
return;
}
// 若遇到指定 key ，则更新对应 val
if (buckets[j].key == key) {
buckets[j].val = val;
return;
}
}
}
/* 删除操作 */
public void remove(int key) {
int index = hashFunc(key);
// 线性探测，从 index 开始向后遍历
for (int i = 0; i < capacity; i++) {
// 计算桶索引，越过尾部返回头部
int j = (index + i) % capacity;
// 若遇到空桶，说明无此 key ，则直接返回
if (buckets[j] == null) {
return;
}
// 若遇到指定 key ，则标记删除并返回
if (buckets[j].key == key) {
buckets[j] = removed;
size -= 1;
return;
}
}
}
/* 扩容哈希表 */
private void extend() {
// 暂存原哈希表
Pair[] bucketsTmp = buckets;
// 初始化扩容后的新哈希表
capacity *= extendRatio;
buckets = new Pair[capacity];
size = 0;
// 将键值对从原哈希表搬运至新哈希表
foreach (Pair pair in bucketsTmp) {
if (pair != null && pair != removed) {
put(pair.key, pair.val);
}
}
}
/* 打印哈希表 */
public void print() {
foreach (Pair pair in buckets) {
if (pair != null) {
Console.WriteLine(pair.key + " -> " + pair.val);
} else {
Console.WriteLine("null");
}
}
}
}
```
=== "Swift"
```swift title="hash_map_open_addressing.swift"
[class]{Pair}-[func]{}
[class]{HashMapOpenAddressing}-[func]{}
```
=== "Zig"
```zig title="hash_map_open_addressing.zig"
[class]{Pair}-[func]{}
[class]{HashMapOpenAddressing}-[func]{}
```
=== "Dart"
```dart title="hash_map_open_addressing.dart"
/* 键值对 */
class Pair {
int key;
String val;
Pair(this.key, this.val);
}
/* 开放寻址哈希表 */
class HashMapOpenAddressing {
late int _size; // 键值对数量