JavaScript - Queues(Deque)

Data Structures and Algorithms With Javascript
(O'Reilly Media)
Michael McMillan(著)

開発環境

• OS X Yosemite - Apple (OS)
• Emacs (Text Editor)
• JavaScript (プログラミング言語)
• SpiderMonkey (JavaScript engine)

Data Structures and Algorithms With Javascript (Michael McMillan(著)、O'Reilly Media)のChapter 5(Queues)、Exercises 1.(No. 3595)を解いてみる。

Exercises 1.(No. 3595)

JavaScript(Emacs)

/*jslint         browser : true, continue : true,
  devel  : true, indent  : 4,    maxerr   : 50,
  newcap : true, nomen   : true, plusplus : false,
  regexp : true, sloppy  : true, vars     : false,
  white  : false
*/

/*global print */
var Queue = function () {
        this.data_store = [];
    },
    Deque = function () {
        this.data_store = [];
    },
    deque,
    i;

Queue.prototype.enqueue = function (element) {
    this.data_store.push(element);
};
Queue.prototype.dequeue = function () {
    return this.data_store.shift();
};
Queue.prototype.front = function () {
    return this.data_store[0];
};
Queue.prototype.back = function () {
    return this.data_store[this.data_store.length - 1];
};
Queue.prototype.toString = function () {
    var result = '',
        i,
        max;
    for (i = 0, max = this.data_store.length; i < max - 1; i += 1) {
        result += this.data_store[i] + ',';
    }
    result += this.data_store[i];
    return result;
};
Queue.prototype.isEmpty = function () {
    return this.data_store.length === 0 ? true : false;
};
Queue.prototype.count = function () {
    return this.data_store.length;
};

Deque.prototype = new Queue();
Deque.constructor = Deque;
Deque.prototype.addFirst = function (element) {
    this.data_store.unshift(element);
};
Deque.prototype.addLast = function (element) {
    this.enqueue(element);
};
Deque.prototype.removeFirst = function () {
    return this.dequeue();
};
Deque.prototype.removeLast = function () {
    return this.data_store.pop();
};
Deque.prototype.getFirst = function () {
    return this.front();
};
Deque.prototype.getLast = function () {
    return this.back();
};
deque = new Deque();

for (i = 0; i < 10; i += 1) {
    deque.addLast(i);
}
print(deque);
for (i = 0; i < 10; i += 1) {
    deque.addFirst(i);
}
print(deque);
print(deque.removeFirst());
print(deque);
print(deque.removeLast());
print(deque);
print(deque.count());
print(deque.isEmpty());
print((new Deque()).count());
print((new Deque()).isEmpty());

出力結果(Terminal, shell, SpiderMonkey)

$ js sample1.js
0,1,2,3,4,5,6,7,8,9
9,8,7,6,5,4,3,2,1,0,0,1,2,3,4,5,6,7,8,9
9
8,7,6,5,4,3,2,1,0,0,1,2,3,4,5,6,7,8,9
9
8,7,6,5,4,3,2,1,0,0,1,2,3,4,5,6,7,8
18
false
0
true
$