链表
数组的缺点
在java语言下, 数组的性能存在缺陷
- 数组定以后长度较为固定, 当进行插入和删除操作后都要对长度进行修改
- 数组删除和插入后,其他元素也要修改位置, 使得操作的消耗性能高
链表
链表是一堆节点的集合,每一个节点都有一个对象来指向他的后继,这样链接起来的节点就是链表 指向下一个节点的索引称为链
- 链表删除： 上一个节点指向下一个节点
- 链表插入： 上一个节点指向新的节点，新的节点指向下一个节点
function Node(element) {
this.element = element
this.next = null
}
function LList() {
this.head = new Node('head')
}
LList.prototype = {
find: function(item) {
var currNode = this.head
while(currNode.element != item) {
currNode = currNode.next
}
return currNode
},
findPrev: function(item) {
var current = this.head
while(current.next != null && current.next.element != item) {
current = current.next
}
return current
},
insert: function(newElement, item) {
var newNode = new Node(newElement)
var current = this.find(item)
newNode.next = current.next
current.next = newNode
},
remove: function(item) {
var prevNode = this.findPrev(item)
var currentNode = this.find(item)
prevNode.next = currentNode.next
},
display: function() {
var arr = []
var current = this.head
while(current.next != null) {
arr.push(current.element)
current = current.next
}
return arr
}
}
var cities = new LList
cities.insert('Conway', 'head')
cities.insert('Russellvitlle', 'Conway')
cities.insert('Alma', 'Russellvitlle')
cities.display()
cities.remove("Russellvitlle")
双向链表
function Node(element) {
this.element = element
this.prev = null
this.next = null
}
function DLList() {
this.head = new Node('head')
}
DLList.prototype = {
find: function (item) {
var current = this.head
while (current.element != item) {
current = current.next
}
return current
},
findLast: function () {
var current = this.head
while (current.next != null) {
current = current.next
}
return current
},
insert: function (newElement, item) {
var newNode = new Node(newElement)
var current = this.find(item)
newNode.next = current.next
newNode.prev = current
current.next = newNode
},
remove: function (item) {
var prevNode = this.find(this.find(item).prev.element)
var nextNode = this.find(this.find(item).next.element)
var target = this.find(item)
prevNode.next = target.next
nextNode.prev = target.prev
target.prev = null
target.next = null
},
display: function () {
var arr = []
var current = this.head
while (current.next != null) {
arr.push(current.element)
current = current.next
}
arr.push(current.element)
return arr
},
displayReverse: function () {
var arr = []
var lastNode = this.findLast()
while (lastNode.prev != null) {
arr.push(lastNode.element)
lastNode = lastNode.prev
}
arr.push(current.element)
return arr
},
advance: function (element, n) {
var currentNode = this.find(element)
var i = 0
var targetNode = this.find(element)
while (i < n) {
targetNode = targetNode.prev
i++
}
console.log(currentNode, targetNode)
this.remove(currentNode.element)
this.insert(currentNode.element, targetNode.prev.element)
}
}
var step = new DLList()
step.insert('create', 'head')
step.insert('test','create')
step.insert('open', 'test')
step.insert('use', 'open')
step.insert('end', 'use')
step.advance('use', 3)
step.display()
循环链表
循环链表类似于单项链表 在定义时 head.next = head
display: function() {
var arr = []
var current = this.head
while(current.next!= null && current.next.element != 'head') {
arr.push(current.element)
current = current.next
}
return arr
}
advance
将当前节点提前N个位置，首先找到当前节点和目标节点
将当前节点删除，然后将他插入在目标节点的前面
advance: function (element, n) {
var currentNode = this.find(element)
var i = 0
var targetNode = this.find(element)
while (i < n) {
targetNode = targetNode.prev
i++
}
console.log(currentNode, targetNode)
this.remove(currentNode.element)
this.insert(currentNode.element, targetNode.prev.element)
}
完整代码
/**
* 链表
*/
// function Node(element) {
// this.element = element
// this.next = null
// }
// function LList() {
// this.head = new Node('head')
// }
// LList.prototype = {
// find: function(item) {
// var currNode = this.head
// while(currNode.element != item) {
// currNode = currNode.next
// }
// return currNode
// },
// findPrev: function(item) {
// var current = this.head
// while(current.next != null && current.next.element != item) {
// current = current.next
// }
// return current
// },
// insert: function(newElement, item) {
// var newNode = new Node(newElement)
// var current = this.find(item)
// newNode.next = current.next
// current.next = newNode
// },
// remove: function(item) {
// var prevNode = this.findPrev(item)
// var currentNode = this.find(item)
// prevNode.next = currentNode.next
// },
// display: function() {
// var arr = []
// var current = this.head
// while(current.next != null) {
// arr.push(current.element)
// current = current.next
// }
// return arr
// }
// }
// var cities = new LList
// cities.insert('Conway', 'head')
// cities.insert('Russellvitlle', 'Conway')
// cities.insert('Alma', 'Russellvitlle')
// cities.display()
// cities.remove("Russellvitlle")
/*
* 双向链表
*/
// function Node(element) {
// this.element = element
// this.prev = null
// this.next = null
// }
// function DLList() {
// this.head = new Node('head')
// }
// DLList.prototype = {
// find: function (item) {
// var current = this.head
// while (current.element != item) {
// current = current.next
// }
// return current
// },
// findLast: function () {
// var current = this.head
// while (current.next != null) {
// current = current.next
// }
// return current
// },
// insert: function (newElement, item) {
// var newNode = new Node(newElement)
// var current = this.find(item)
// newNode.next = current.next
// newNode.prev = current
// current.next = newNode
// },
// remove: function (item) {
// var prevNode = this.find(this.find(item).prev.element)
// var nextNode = this.find(this.find(item).next.element)
// var target = this.find(item)
// prevNode.next = target.next
// nextNode.prev = target.prev
// target.prev = null
// target.next = null
// },
// display: function () {
// var arr = []
// var current = this.head
// while (current.next != null) {
// arr.push(current.element)
// current = current.next
// }
// arr.push(current.element)
// return arr
// },
// displayReverse: function () {
// var arr = []
// var lastNode = this.findLast()
// while (lastNode.prev != null) {
// arr.push(lastNode.element)
// lastNode = lastNode.prev
// }
// arr.push(current.element)
// return arr
// },
// advance: function (element, n) {
// var currentNode = this.find(element)
// var i = 0
// var targetNode = this.find(element)
// while (i < n) {
// targetNode = targetNode.prev
// i++
// }
// console.log(currentNode, targetNode)
// this.remove(currentNode.element)
// this.insert(currentNode.element, targetNode.prev.element)
// }
// }
// var step = new DLList()
// step.insert('create', 'head')
// step.insert('test','create')
// step.insert('open', 'test')
// step.insert('use', 'open')
// step.insert('end', 'use')
// step.advance('use', 3)
// step.display()
/*
* 循环链表 约瑟夫问题
*/
function Node(element) {
this.element = element
this.next = null
}
function CyLList() {
this.head = new Node('head')
this.head.next = this.head
}
CyLList.prototype = {
find: function (item) {
var currNode = this.head
while (currNode.element != item) {
currNode = currNode.next
}
return currNode
},
findPrev: function (item) {
var current = this.head
while (current.next != null && current.next.element != item) {
current = current.next
}
return current
},
insert: function (newElement, item) {
var newNode = new Node(newElement)
var current = this.find(item)
newNode.next = current.next
current.next = newNode
},
remove: function (item) {
var prevNode = this.findPrev(item)
var currentNode = this.find(item)
prevNode.next = currentNode.next
},
display: function () {
var arr = []
var current = this.head
while (current.next != null && current.next.element != 'head') {
arr.push(current.element)
current = current.next
}
arr.push(current.element)
return arr
}
}
// 约瑟夫问题，N个人围成一圈，从头数数，数到M的人去死，然后从头数数
function test(n, m) {
var cycle = new CyLList()
var people = []
for (let i = 0; i < n; i++) {
people.push(new Node(i))
if (i == 0) {
cycle.insert(i, 'head')
} else {
cycle.insert(i, i - 1)
}
}
var index = 0
var len = cycle.display().length - 1
while (cycle.display().length - 1 > m || cycle.display().length - 1 == m) {
index = (index + m - 1) % len
console.log(index, people[index].element + ' killed')
cycle.remove(people[index].element)
// people.splice(index,1)
console.log(cycle.display())
}
}
// 约瑟夫问题的数组解法
function countOff(num, m) {
let players = [];
for (let i = 1; i <= num; i++) {
players.push(i);
}
let flag = 0
while (players.length >= m) {
let length = players.length
flag = (flag + m - 1) % length
console.log(`${players[flag]} is out`, flag)
players.splice(flag, 1)
console.log("剩下：" + players);
}
}
countOff(5, 3)
