数据结构Typescript之哈希表实现详解

function HashCode(str) { // 散列函数
    let address = 0
    for (let i = 0; i < str.length; i++) {
        address += str.charCodeAt(i)
    }
    return address % 37 // 生成的哈希码
}
let table = {} // 哈希表
let keyValuePair = { key: "苹果手机", value: "4999元" } // 哈希表的基本单元: 键值对
table[HashCode(keyValuePair.key)] = keyValuePair // table添加对象，属性为哈希码，值为keyValuePair
console.log(table) // 输出哈希表: table { 28: { key: "苹果手机", value: "4999元" } }

console.log(HashCode('Mike')) // 20
console.log(HashCode('Meki')) // 20
console.log(HashCode('keMi')) // 20

class keyValuePair {
    key: any
    value: any
    constructor(key: any, value: any) {
        this.key = key
        this.value = value
    }
}

class HashTable {
    length: number
    table: { [index: number]: LinkedList }
    constructor() {
        this.length = 0
        this.table = {}
    }
}

set(key: any, value: any): HashTable {
    if (this.table[HashCode(key)] === undefined) {
        this.table[HashCode(key)] = new LinkedList()
    }
    this.table[HashCode(key)].insert(new keyValuePair(key, value))
    this.length++
    return this
}

get(key: any): (void | any) {
    if (this.isEmpty()) {
        throw new Error(`HashTable is empty`)
    } else if (this.table[HashCode(key)] === undefined) {
        throw new Error(`${key} is not defined`)
    } else {
        let current: (null | LinkedListNode) = this.table[HashCode(key)].head
        while (current !== null) {
            if (key === current!.element!.key) {
                return current!.element!.value
            }
            current = current!.next
        }
        if (!current) { throw new Error(`${key} does not exist`) }
    }
}

remove(key: any): HashTable {
    if (this.isEmpty()) {
        throw new Error(`HashTable is empty`)
    } else if (this.table[HashCode(key)] === undefined) {
        throw new Error(`${key} is not defined`)
    } else if (this.table[HashCode(key)].length === 1) {
        delete this.table[HashCode(key)]
    } else if (this.table[HashCode(key)].length > 1) {
        let current: (null | LinkedListNode) = this.table[HashCode(key)].head
        for (let i = 0; i < this.table[HashCode(key)].length; i++) {
            if (key === current!.element!.key) {
                this.table[HashCode(key)].remove(i)
                break
            }
            current = current!.next
        }
        if (!current) { throw new Error(`${key} does not exist`) }
    }
    this.length--
    return this
}