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Js dev #93

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Dec 12, 2022
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Js dev #93

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885be1e
add remaining code for Array and LinkedList
IsChristina Dec 12, 2022
35d4208
merge codes
IsChristina Dec 12, 2022
dc3ac1f
add ;
IsChristina Dec 12, 2022
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52 changes: 26 additions & 26 deletions codes/javascript/chapter_array_and_linkedlist/array.js
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Expand Up @@ -7,24 +7,24 @@
/* 随机访问元素 */
function randomAccess(nums){
// 在区间 [0, nums.length) 中随机抽取一个数字
const random_index = Math.floor(Math.random() * nums.length)
const random_index = Math.floor(Math.random() * nums.length);
// 获取并返回随机元素
random_num = nums[random_index]
return random_num
random_num = nums[random_index];
return random_num;
}

/* 扩展数组长度 */
// 请注意，Python 的 list 是动态数组，可以直接扩展
// 为了方便学习，本函数将 list 看作是长度不可变的数组
function extend(nums, enlarge){
// 初始化一个扩展长度后的数组
let res = new Array(nums.length + enlarge).fill(0)
let res = new Array(nums.length + enlarge).fill(0);
// 将原数组中的所有元素复制到新数组
for(let i=0; i<nums.length;i++){
res[i] = nums[i]
res[i] = nums[i];
}
// 返回扩展后的新数组
return res
return res;
}

/* 在数组的索引 index 处插入元素 num */
Expand All @@ -41,59 +41,59 @@ function insert(nums, num, index){
function remove(nums, index){
// 把索引 index 之后的所有元素向前移动一位
for (let i = index; i < nums.length - 1; i++) {
nums[i] = nums[i + 1]
nums[i] = nums[i + 1];
}
}

/* 遍历数组 */
function traverse(nums){
let count = 0
let count = 0;
// 通过索引遍历数组
for (let i = 0; i < nums.length; i++) {
count++;
}
// 直接遍历数组
for(let num of nums){
count += 1
count += 1;
}
}

/* 在数组中查找指定元素 */
function find(nums, target){
for (let i = 0; i < nums.length; i++) {
if (nums[i] == target)
if (nums[i] === target)
return i;
}
return -1
return -1;
}


/* Driver Codes*/
/* 初始化数组 */
var arr = new Array(5).fill(0)
console.log("数组 arr =", arr)
var nums = [1, 3, 2, 5, 4]
console.log("数组 nums =", nums)
var arr = new Array(5).fill(0);
console.log("数组 arr =", arr);
var nums = [1, 3, 2, 5, 4];
console.log("数组 nums =", nums);

/* 随机访问 */
random_num = randomAccess(nums)
console.log("在 nums 中获取随机元素", random_num)
random_num = randomAccess(nums);
console.log("在 nums 中获取随机元素", random_num);

/* 长度扩展 */
nums = extend(nums, 3)
console.log("将数组长度扩展至 8 ，得到 nums =", nums)
nums = extend(nums, 3);
console.log("将数组长度扩展至 8 ，得到 nums =", nums);

/* 插入元素 */
insert(nums, 6, 3)
console.log("在索引 3 处插入数字 6 ，得到 nums =", nums)
insert(nums, 6, 3);
console.log("在索引 3 处插入数字 6 ，得到 nums =", nums);

/* 删除元素 */
remove(nums, 2)
console.log("删除索引 2 处的元素，得到 nums =", nums)
remove(nums, 2);
console.log("删除索引 2 处的元素，得到 nums =", nums);

/* 遍历数组 */
traverse(nums)
traverse(nums);

/* 查找元素 */
var index = find(nums, 3)
console.log("在 nums 中查找元素 3 ，得到索引 =", index)
var index = find(nums, 3);
console.log("在 nums 中查找元素 3 ，得到索引 =", index);
84 changes: 84 additions & 0 deletions codes/javascript/chapter_array_and_linkedlist/linked_list.js
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@@ -0,0 +1,84 @@
/**
* File: linked_list.js
* Created Time: 2022-12-12
* Author: IsChristina ([email protected])
*/

const PrintUtil = require("../include/PrintUtil");
const ListNode = require("../include/ListNode");

/* 在链表的结点 n0 之后插入结点 P */
function insert(n0, P) {
let n1 = n0.next;
n0.next = P;
P.next = n1;
}

/* 删除链表的结点 n0 之后的首个结点 */
function remove(n0) {
if (!n0.next)
return;
// n0 -> P -> n1
let P = n0.next;
let n1 = P.next;
n0.next = n1;
}

/* 访问链表中索引为 index 的结点 */
function access(head, index) {
for (let i = 0; i < index; i++) {
head = head.next;
if (!head)
return null;
}
return head;
}

/* 在链表中查找值为 target 的首个结点 */
function find(head, target) {
let index = 0;
while (head !== null) {
if (head.val === target)
return index;
head = head.next;
index++;
}
return -1;
}

/* Driver Code */

/* 初始化链表 */
// 初始化各个结点
const n0 = new ListNode(1);
const n1 = new ListNode(3);
const n2 = new ListNode(2);
const n3 = new ListNode(5);
const n4 = new ListNode(4);
// 构建引用指向
n0.next = n1;
n1.next = n2;
n2.next = n3;
n3.next = n4;
console.log("初始化的链表为");
PrintUtil.printLinkedList(n0);

/* 插入结点 */
insert(n0, new ListNode(0));
console.log("插入结点后的链表为");
PrintUtil.printLinkedList(n0);

/* 删除结点 */
remove(n0);
console.log("删除结点后的链表为");
PrintUtil.printLinkedList(n0);

/* 访问结点 */
var node = access(n0, 3);
console.log("链表中索引 3 处的结点的值 = " + node.val);

/* 查找结点 */
var index = find(n0, 2);
console.log("链表中值为 2 的结点的索引 = " + index);


59 changes: 59 additions & 0 deletions codes/javascript/chapter_array_and_linkedlist/list.js
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/**
* File: list.js
* Created Time: 2022-12-12
* Author: IsChristina ([email protected])
*/

/* 初始化列表 */
var list = [1, 3, 2, 5, 4];
console.log("列表 list = " + list);

/* 访问元素 */
var num = list[1];
console.log("访问索引 1 处的元素，得到 num = " + num);

/* 更新元素 */
list[1] = 0;
console.log("将索引 1 处的元素更新为 0 ，得到 list = " + list);

/* 清空列表 */
list = [];
console.log("清空列表后 list = " + list);

/* 尾部添加元素 */
list.push(1);
list.push(3);
list.push(2);
list.push(5);
list.push(4);
console.log("添加元素后 list = " + list);

/* 中间插入元素 */
list.splice(3, 0, 6);
console.log("在索引 3 处插入数字 6 ，得到 list = " + list);

/* 删除元素 */
list.splice(3, 1);
console.log("删除索引 3 处的元素，得到 list = " + list);

/* 通过索引遍历列表 */
var count = 0;
for (let i = 0; i < list.length; i++) {
count++;
}

/* 直接遍历列表元素 */
count = 0;
for (const n of list) {
count++;
}

/* 拼接两个列表 */
var list1 = [ 6, 8, 7, 10, 9 ];
list.push(...list1)
console.log("将列表 list1 拼接到 list 之后，得到 list = " + list);

/* 排序列表 */
list.sort((a, b) => a - b);
console.log("排序列表后 list = " + list);

143 changes: 143 additions & 0 deletions codes/javascript/chapter_array_and_linkedlist/my_list.js
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/**
* File: my_list.js
* Created Time: 2022-12-12
* Author: IsChristina ([email protected])
*/

/* 列表类简易实现 */
class MyList {
nums; // 数组（存储列表元素）
_capacity = 10; // 列表容量
_size = 0; // 列表长度（即当前元素数量）
extendRatio = 2; // 每次列表扩容的倍数

/* 构造函数 */
constructor() {
this.nums = new Array(this._capacity);
}

/* 获取列表长度（即当前元素数量）*/
get size() {
return this._size;
}

/* 获取列表容量 */
get capacity() {
return this._capacity;
}

/* 访问元素 */
get(index) {
// 索引如果越界则抛出异常，下同
if (index >= this._size)
throw new Error("索引越界");
return this.nums[index];
}

/* 更新元素 */
set(index, num) {
if (index >= this._size)
throw new Error("索引越界");
this.nums[index] = num;
}

/* 尾部添加元素 */
add(num) {
//元素数量超出容量时，触发扩容机制
if (this._size === this._capacity)
this.extendCapacity();
this.nums[this._size] = num;
// 更新元素数量
this._size++;
}

/* 中间插入元素 */
insert(index, num) {
if (index >= this._size)
throw new Error("索引越界");
// 元素数量超出容量时，触发扩容机制
if (this._size === this._capacity)
this.extendCapacity();
// 将索引 index 以及之后的元素都向后移动一位
for (let j = this._size - 1; j >= index; j--) {
this.nums[j + 1] = this.nums[j];
}
this.nums[index] = num;
// 更新元素数量
this._size++;
}

/* 删除元素 */
remove(index) {
if (index >= this._size)
throw new Error("索引越界");
let num = this.nums[index];
// 将索引 index 之后的元素都向前移动一位
for (let j = index; j < this._size - 1; j++) {
this.nums[j] = this.nums[j + 1];
}
// 更新元素数量
this._size--;
// 返回被删除元素
return num;
}

/* 列表扩容 */
extendCapacity() {
// 新建一个长度为 size 的数组，并将原数组拷贝到新数组
this.nums = this.nums.concat(
new Array(this.capacity * (this.extendRatio - 1))
);
// 更新列表容量
this._capacity = this.nums.length;
}

/* 将列表转换为数组 */
toArray() {
let size = this.size;
// 仅转换有效长度范围内的列表元素
let nums = new Array(size);
for (let i = 0; i < size; i++) {
nums[i] = this.get(i);
}
return nums;
}
}

/* Driver Code */

/* 初始化列表 */
var list = new MyList();
/* 尾部添加元素 */
list.add(1);
list.add(3);
list.add(2);
list.add(5);
list.add(4);
console.log("列表 list = " + list.toArray().toString() +
" ，容量 = " + list.capacity + " ，长度 = " + list.size);

/* 中间插入元素 */
list.insert(3, 6);
console.log("在索引 3 处插入数字 6 ，得到 list = " + list.toArray().toString());

/* 删除元素 */
list.remove(3);
console.log("删除索引 3 处的元素，得到 list = " + list.toArray().toString());

/* 访问元素 */
var num = list.get(1);
console.log("访问索引 1 处的元素，得到 num = " + num);

/* 更新元素 */
list.set(1, 0);
console.log("将索引 1 处的元素更新为 0 ，得到 list = " + list.toArray().toString());

/* 测试扩容机制 */
for (let i = 0; i < 10; i++) {
// 在 i = 5 时，列表长度将超出列表容量，此时触发扩容机制
list.add(i);
}
console.log("扩容后的列表 list = " + list.toArray().toString() +
" ，容量 = " + list.capacity + " ，长度 = " + list.size);

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