Live Note

class Array {
  constructor(size = 10) {
    this.arr = [] // 数组
    this.size = size // 最大长度
    this.elems = 0 // 成员数量
  }

  add(elem) {
    if (this.arr.length == this.size) {
      console.log("Array is full")
      return
    }
    this.arr[this.elems++] = elem
    return true
  }

  find(elem) {
    for (let i = 0, len = this.elems; i < len; i++) {
      if (this.arr[i] == elem) return i
    }
    return -1
  }

  delete(elem) {
    let index = this.find(elem)
    if (index == -1) {
      console.log("Element not found")
      return
    }
    for (let i = index, len = this.elems - 1; i < len; i++)
      this.arr[i] = this.arr[i + 1]
    this.elems--
    return true
  }

  update(oldVal, newVal) {
    // only use for unique element
    let index = this.find(oldVal)
    if (index == -1) {
      console.log("Element not found")
      return
    }
    this.arr[index] = newVal
    return true
  }

  display() {
    let srt = ""
    for (let i = 0, len = this.elems; i < len; i++) {
      srt += "" + this.arr[i] + " "
    }
    console.log(srt)
  }

  length() {
    return this.elems
  }
}
var arr = new Array()
arr.add(1)
arr.add(2)
arr.add(3)
arr.add(4)
arr.display()
console.log(arr.length())

class Queue {
  constructor(size = 10) {
    this.size = size // 队列最大长度
    this.top = 0 // 首位置
    this.bottom = -1 // 尾位置
    this.elems = 0 // 成员个数
    this.arr = [] // 队列
  }

  add(elem) {
    if (this.elems == this.size) {
      console.log("Queue is full")
      return
    }
    if (this.bottom == this.size - 1) {
      // 循环队列
      this.bottom = -1
    }
    this.arr[++this.bottom] = elem
    this.elems++
    return true
  }

  out() {
    if (this.elems == 0) {
      console.log("Queue is empty")
      return
    }
    let elem = this.arr[this.top]
    this.arr[this.top] = null
    this.top++
    if (this.top == this.size) {
      this.top = 0
    }
    this.elems--
    return elem
  }
}
var queue = new Queue()
queue.add(3)
queue.add(2)
console.log(queue.out())
console.log(queue.out())
console.log(queue.out())

class Stack {
  constructor(size = 10) {
    this.arr = [] // 栈
    this.size = size // 最大长度
    this.top = -1 // 栈顶
  }

  push(elem) {
    if (this.top == this.size) {
      this.size *= 2
    }
    this.arr[++this.top] = elem
    return true
  }

  pop() {
    let elem = this.arr[this.top--]
    return elem
  }

  peekTop() {
    if (this.top == -1) {
      console.log("stack is empty")
      return
    }
    return this.arr[this.top]
  }

  print() {
    let str = ""
    for (let i = 0; i <= this.top; i++) {
      str += this.arr[i] + " "
    }
    console.log(str)
  }
}
var stack = new Stack()
stack.push(1)
stack.push(2)
stack.pop()
console.log(stack.peekTop())

class Node {
  constructor(data = -1, prev = null, next = null) {
    this.data = data
    this.prev = prev // 向前指针
    this.next = next // 向后指针
  }
}

class LinkList {
  constructor() {
    this.head = this.tail = null // 首、尾指针
    this.size = 0 // 元素个数
  }

  addHead(elem) {
    let elemNode = new Node(elem)
    if (this.size == 0) {
      this.head = this.tail = elemNode
      this.size++
    } else {
      this.head.prev = elemNode
      elemNode.next = this.head
      this.head = elemNode
      this.size++
    }
    return true
  }

  deleteHead() {
    if (this.size != 0) {
      let elem = this.head.data
      this.head.prev = null
      this.head = this.head.next
      this.size--
      return elem
    } else {
      console.log("list is empty")
      return
    }
  }

  addTail(elem) {
    let elemNode = new Node(elem)
    if (this.size == 0) {
      this.head = this.tail = elemNode
      this.size++
    } else {
      elemNode.prev = this.tail
      this.tail.next = elemNode
      this.tail = elemNode
      this.size++
    }
    return true
  }

  deleteTail() {
    if (this.size != 0) {
      let elem = this.tail.data
      this.tail.next = null
      this.tail = this.tail.prev
      this.size--
      return elem
    } else {
      console.log("list is empty")
      return
    }
  }

  display() {
    let current = this.head,
      count = this.size,
      str = ""
    while (count > 0) {
      str += current.data + " "
      current = current.next
      count--
    }
    console.log(str)
  }
}
let linklist = new LinkList()
linklist.addHead(1)
linklist.addHead(2)
linklist.addHead(3)
linklist.deleteHead()
linklist.addTail(4)
linklist.display()