链表的实现
一. 单向链表
// Node类
function Node (element) {
this.element = element;
this.next = null;
}
// LinkedList类
function LList () {
this.head = new Node('head');
this.find = find;
this.insert = insert;
this.findPrevious = findPrevious;
this.remove = remove;
this.display = display;
}
// 查找
function find (item) {
let currNode = this.head;
while (currNode.element !== item) {
currNode = currNode.next;
}
return currNode;
}
// 插入
function insert (newElement, item) {
let newNode = new Node(newElement);
let current = this.find(item);
newNode.next = current.next;
current.next = newNode;
}
// 显示
function display () {
let currNode = this.head;
while (currNode.next !== null) {
currNode = currNode.next;
console.log(currNode.element);
}
}
// 检查下一个节点
function findPrevious (item) {
let currNode = this.head;
while (currNode.next !== null && currNode.next.element !== item) {
currNode = currNode.next;
}
return currNode;
}
// 删除
function remove (item) {
let prevNode = this.findPrevious(item);
if (prevNode.next !== null) {
prevNode.next = prevNode.next.next;
}
}
二. 双向链表
function Node (element) {
this.element = element;
this.next = null;
this.previous = null;
}
function DList () {
this.head = new Node('head');
this.find = find;
this.insert = insert;
this.display = display;
this.remove = remove;
this.findLast = findLast;
this.dispReverse = dispReverse;
}
function dispReverse () {
let currNode = this.head;
currNode = this.findLast();
while (currNode !== null && currNode.element !== 'head') {
console.log(currNode.element);
currNode = currNode.previous;
}
}
function findLast () {
let currNode = this.head;
while (currNode.next !== null) {
currNode = currNode.next;
}
return currNode;
}
function remove (item) {
let currNode = this.find(item);
if (currNode.next !== null) {
currNode.previous.next = currNode.next;
currNode.next.previous = currNode.previous;
currNode.next = null;
currNode.previous = null;
}
}
function display () {
let currNode = this.head;
while (currNode.next !== null) {
console.log(currNode.next.element);
currNode = currNode.next;
}
}
function find (item) {
let currNode = this.head;
while (currNode.element !== item) {
currNode = currNode.next;
}
return currNode;
}
function insert (newElement, item) {
let newNode = new Node(newElement);
let currNode = this.find(item);
newNode.next = currNode.next;
newNode.previous = currNode;
currNode.next = newNode;
}
三. 循环链表
// Node类
function Node (element) {
this.element = element;
this.next = null;
}
// LinkedList类
function CList () {
this.head = new Node('head');
// 修改
this.head.next = this.head;
this.find = find;
this.insert = insert;
this.findPrevious = findPrevious;
this.remove = remove;
this.display = display;
}
// 其他
// ...
练习
一. 实现advance(n)方法，使当前节点向前移动n个节点。
// 向前移动一位
DList.prototype.goPrevious = function (thisNode) {
let node1, node2, node3, node4;
if (thisNode.previous.element !== 'head') {
node1 = thisNode.previous.previous;
node2 = thisNode.previous;
node3 = thisNode;
node4 = thisNode.next;
// 位置调整
node1.next = node3;
node3.previous = node1;
node3.next = node2;
node2.previous = node3;
node2.next = node4;
node4.previous = node2;
}
};
DList.prototype.advance = function (n, item) {
let currNode = this.find(item);
while (n--) {
this.goPrevious(currNode);
}
};
// 示例
let names = new DList();
names.insert('Mazey', 'head');
names.insert('Cherrie', 'Mazey');
names.insert('John', 'Cherrie');
names.insert('Luna', 'John');
names.insert('Ada', 'Luna');
names.display();
console.log('---');
names.advance(2, 'Luna');
names.display(); // Mazey, Luna, Cherrie, John, Ada
二. 实现back(n)方法，使当前节点向后移动n个节点。
// 向前移动一位
DList.prototype.goNext = function (thisNode) {
let node1, node2, node3, node4;
if (thisNode.next.element !== null) {
node1 = thisNode.previous;
node2 = thisNode;
node3 = thisNode.next;
node4 = thisNode.next.next;
// 位置调整
node1.next = node3;
node3.previous = node1;
node3.next = node2;
node2.previous = node3;
node2.next = node4;
node4.previous = node2;
}
};
DList.prototype.back = function (n, item) {
let currNode = this.find(item);
while (n--) {
this.goNext(currNode);
}
};
// 示例
let names = new DList();
names.insert('Mazey', 'head');
names.insert('Cherrie', 'Mazey');
names.insert('John', 'Cherrie');
names.insert('Luna', 'John');
names.insert('Ada', 'Luna');
names.display();
console.log('---');
names.back(2, 'Cherrie');
names.display(); // Mazey, John, Luna, Cherrie, Ada