实现栈结构

//创建栈function Stack (){    let items = []        this.push = function(element){        items.push(element)    }    this.pop = function(){       return items.pop()    }    this.peek = function(){        return items[items.length - 1]    }    this.isEmpty = function(){        return items.length === 0    }    this.size = function(){        return items.length    }    this.clear = function(){        items = []    }    this.print = function(){        console.log(items.toString())    }}

ES6改造

//使用Symbol添加私有属性class Stack {    let _items = Symbol()    constructor(){        this[_items] = []    }    push(element){        this[_items].push(element)    }}//可以拿到所有的symbol对象Object.getOwnPropertySymbols(Stack)//使用weakMapconst items = new weakMap()class Stack {    constructor(){        items.set(this,[])    }    push(element){        let s = items.get(this)        s.push(element)    }    pop(){        let s = items.get(this)        let r = s.pop()        return r    }}//利用闭包实现私有属性let Stack = (function(){   const items = new WeackMap()      class Stack {    constructor(){        items.set(this,[])    }    push(element){        let s = items.get(this)        s.push(element)    }    pop(){        let s = items.get(this)        let r = s.pop()        return r    }}   return Stack})()

进制转换

//10进制转2进制function divideBy2(decNumber){    var remStack = new Stack(),    rem,    binaryString = '';        while(decNumber > 0){        rem = Math.floor(decNumber % 2)        remStack.push(rem)        decNumber = Math.floor(decNumber / 2)    }        while(!remStack.isEmpty()){        binaryString += remStack.pop().toString()    }}//任意进制转换function baseConverter(decNumber,base){  const remStack = new Stack();  const digits = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';  let number = decNumber;  let rem;  let baseString = '';  if (!(base >= 2 && base <= 36)) {    return '';  }  while (number > 0) {    rem = Math.floor(number % base);    remStack.push(rem);    number = Math.floor(number / base);  }  while (!remStack.isEmpty()) {    baseString += digits[remStack.pop()];  }  return baseString;}

平衡圆括号

function balancedSymbols(symbols){    const stack =  new Stack()    const opens = `([{`    const closers = `)]}`        let balanced = true    let index = 0    let symbol    let top        while(index < symbols.length && balanced){        symbol = symbols[index]                if(opens.indexOf(symbol) >= 0){            stack.push(symbol)        } else if(stack.isEmpty()){            balanced = false        } else {            top = stack.pop()            if(!(opens.indexOf(top) === closers.indexOf(symbol))){                balanced = false            }        }                index ++    }    return balanced && stack.isEmpty()}

汉诺塔

递归，即定义一组基本操作，这组操作将规模小一点（或大一点）的操作当做一个整体——无需关心它的细节，只当它已经完成了——然后执行剩下的操作。而在更小或更大的规模中也依此操作，直到规模达到预定值。

function towerOfHanoi(plates,source,helper,dest,sourceName,helperName,destName,moves = []){    if(plates <= 0){        return moves    }    if(plates === 1){        dest.push(source.pop())        const move = {}        move[sourceName] = source.toString()        move[helperName] = helper.toString()        move[destName] = dest.toString()        moves.push(move)    }    else {        towerOfHanoi(            plates - 1,            source,            dest,            helper,            sourceName,            destName,            helperName,            moves        )        dest.push(source.pop())        const move = {}        move[sourceName] = source.toString()        move[helperName] = helper.toString()        move[destName] = dest.toString()        moves.push(move)        towerOfHanoi(            plates - 1,            helper,            source,            dest,            helperName,            sourceName,            destName,            moves        )    }    return moves}function hanoiStack(plates){    const source = new Stack()    const dest = new Stack()    const helper = new Stack()        for(let i = plates; i > 0; i --){        source.push(i)    }        return towerOfHanoi(        plates,        source,        helper,        dest,        source,        helper,        dest    )}function hanoi(plates,source,helper,dest,moves = []){    if(plates <= 0){        return moves    }    if(plates === 1){        moves.push([source,dest])    } else {        hanoi(            plates - 1,            source,            dest,            helper,            moves        )        moves.push([source,dest])    }    return moves}//用栈来实现汉诺塔console.log(hanoiStack(3));//用递归来来实现console.log(hanoi(3, 'source', 'helper', 'dest'));