字典map
map.js
var Dictionary = function() {
var items = {};
// 檢查鍵
this.has = function(key) {
return key in items;
}
// 新增鍵值對
this.set = function(key, value) {
items[key] = value;
}
//通過鍵移除元素
this.delete = function(key) {
if (this.has(key)) {
delete items[key];
return true;
}
return false;
}
// 由鍵獲取值
this.get = function(key) {
return this.has(key) ? items[key] : undefined;
}
//以列表返回字典值
this.values = function() {
var values = [];
for (var k in items) {
if (this.has(k)) {
values.push(items[k])
}
}
return values;
}
//獲取全部鍵名
this.keys = function() {
return Object.keys(items);
}
//獲取私有變數items
this.getItems = function() {
return items;
}
}
複製程式碼例項化
雜湊表(雜湊表)
charCodeAt()
把字元傳為數字
實現雜湊表
hash.js
var HashTable = function() {
var items = [];
//雜湊函式
var loseloseHashCode = function(key) {
var hash = 0;
for (var i = 0; i < key.length; i++) {
hash += key[i].charCodeAt();
}
return hash % 37
}
this.put = function(key, value) {
var position = loseloseHashCode(key)
console.log(position + '-' + value);
items[position] = value;
}
this.remove = function(key) {
items[loseloseHashCode(key)] = undefined
}
this.get = function(key){
return items[loseloseHashCode(key)]
}
this.getItems = function() {
return items;
}
}
複製程式碼例項化
雜湊表衝突解決方案：分離連結法
hash2.js
var LikedList = function() {
//連結串列頭
var head = null
// 連結串列長度
var length = 0
// 輔助類：節點
var Node = function(element) {
this.element = element
this.next = null
}
//連結串列尾新增元素
this.append = function(element) {
var node = new Node(element)
//node={
// element : element
// next : null
// }
if (head == null) {
head = node
} else {
var current = head
while (current.next) {
current = current.next
}
// while迴圈執行完之後 ，current已經是連結串列最後一項了
current.next = node
}
length++
}
//連結串列某一個位置新增元素
this.insert = function(position, element) {
// 越界
if (position > -1 && position < length) {
var node = new Node(element)
if (position == 0) {
var current = head
head = node
head.next = current
} else {
var index = 0
var current = head
var previous = null
while (index < position) {
previous = current
current = current.next
index++
}
previous.next = node
node.next = current
}
length++
}
}
// splice(1,10)
// 沒有移除 ？？？ 拿出來用一下
this.removeAt = function(position) {
if (position > -1 && position < length) {
if (position == 0) {
var current = head
head = current.next
} else {
var current = head
var previous = null
var index = 0
while (index < position) {
previous = current
current = current.next
index++
}
// 跳出迴圈的時候 index == position
previous.next = current.next
}
length--
return current
}
return null
}
this.indexOf = function(element) {
var current = head
var index = 0
while (current) {
if (current.element == element) {
return index
}
current = current.next
index++
}
return -1
}
//removeAt(position) 刪除某個位置的元素
//indexOf(element) 獲取某個元素的位置
this.remove = function(element) {
// length --
return this.removeAt(this.indexOf(element))
}
this.isEmpty = function() {
return length == 0
}
this.size = function() {
return length
}
this.getHead = function() {
return head
}
}
//分離連結
var HashTable_L = function() {
var table = []
// 雜湊函式 key 》 雜湊值 》重複率太高
var loseloseHashCode = function(key) { //Jobs
var hash = 0
for (var i = 0; i < key.length; i++) {
hash += key[i].charCodeAt()
}
return hash % 37
}
var Node = function(key, value) {
this.key = key
this.value = value
}
this.put = function(key, value) {
var position = loseloseHashCode(key)
if (table[position]) {
table[position].append(new Node(key, value))
} else {
var l = new LikedList
table[position] = l
table[position].append(new Node(key, value))
}
}
this.get = function(key) {
var position = loseloseHashCode(key)
if (table[position]) {
// 連結串列線性查詢
var current = table[position].getHead()
while (current) {
if (current.element.key == key) {
return current.element.value
}
current = current.next
}
} else {
return undefined
}
}
this.remove = function(key) {
var position = loseloseHashCode(key)
if (table[position]) {
// 刪除
// remove(element)
var current = table[position].getHead()
while (current) {
if (current.element.key == key) {
// 查詢到對應的key了
table[position].remove(current.element /*Node*/ )
if (table[position].isEmpty()) {
table[position] = undefined
}
return true
}
current = current.next
}
} else {
return false
}
}
this.getTable = function() {
return table
}
}
複製程式碼例項化
雜湊表衝突解決方案：線性探查法
this.put = function(key, value) {
var position = loseloseHashCode(key)
if (table[position] == undefined) {
table[position] = new Node(key, value)
} else {
var index = position + 1;
while (table[index] !== undefined) {
index++
}
table[index] = new Node(key, value)
}
}
複製程式碼
雜湊表衝突解決方案: 利用數學方法生成不重複的雜湊函式
hash4.js
var HashTable = function() {
var items = [];
//不重雜湊函式
var djb2HashCode = function(key) {
var hash = 5381
for (var i = 0; i < key.length; i++) {
hash = hash * 33 + key[i].charCodeAt()
}
return hash % 1013
}
this.put = function(key, value) {
var position = djb2HashCode(key)
console.log(position + '-' + value);
items[position] = value;
}
this.remove = function(key) {
items[djb2HashCode(key)] = undefined
}
this.get = function(key) {
return items[djb2HashCode(key)]
}
this.getItems = function() {
return items;
}
}
複製程式碼例項化
