关于javascript:JavaScript数据结构杂谈双端队列

双端队列是与队列相似的项的有序汇合，其实实质就是队列，只不过是前端与后端都反对插入和删除操作的队列，更实用，所以也就不存在先进先出这种说法了。

咱们能够通过数组来实现，然而为了写出一个更高效得数据结构，应用对象来实现。

class Deque{    constructor(){        this.count= 0;        this.lowestCount = 0;        this.items = {};    }    isEmptry(){        return this.size() === 0;    }    size(){        return this.count - this.lowestCount;    }    clear(){        this.count= 0;        this.lowestCount = 0;        this.items = {};    }    toString(){        if(this.isEmptry()){            return '';        }        let objString = `${this.items[this.lowestCount]}`;        for (let i=this.lowestCount+1;i<this.count;i++) {            objString = `${objString},${this.items[i]}`;        }        return objString;    }    addBack(el){        this.item[this.count]=el;        this.count++;    }    addFront(el){        if(this.isEmptry()){            this.addBack(el);        }else if(this.lowestCount>0){            this.lowestCount--;            this.item[this.lowestCount]=el;        }else{            for(let i=this.count;i>0;i--){                this.item[i]=this.item[i-1];            }            this.count++;            this.lowestCount=0;            this.item[0]=el;        }    }    removeFront(){        if(this.isEmptry()){            return undefined;        }        let c = this.items[this.lowestCount];        delete this.items[this.lowestCount];        this.lowestCount++;        return c;    }    removeBack(){         if (this.isEmpty()) {            return undefined;         }         this.count--;         let c = this.items[this.count];         delete this.items[this.count];         return c;    }    peekFront() {        if (this.isEmpty()) {            return undefined;        }        return this.items[this.lowestCount];    }    peekBack() {        if (this.isEmpty()) {            return undefined;        }        return this.items[this.count - 1];    } }

该内容借鉴于学习javascript数据结构与算法。