集合的實現1--使用對象

集合： 無序不重複

/*
	Set
	集合：不重複並且無序
*/

function Set() {
	var items = {};

	/*集合中添加一個元素*/
	this.add = function(value) {
		if(!this.has(value)) {
			items[value] = value;
			return true;
		}

		return false;
	}

	/*從集合中刪除一個元素*/
	this.remove = function (value) {
		if(this.has(value)) {
			delete items[value];
			return true;
		}

		return false;
	}

	/*判斷集合中是否存在某個元素*/
	this.has = function (value) {
		return items.hasOwnProperty(value);
		// return value in items;
	}

	/*清空集合*/
	this.clear = function () {
		items = {};
	}

	/*集合的大小*/
	this.size = function () {
		var cnt = 0;
		for(var name in items) {
			if(this.has(name)) {
				cnt++
			}
		}

		return cnt;
	}

	/*返回一個包含集合中所有元素的數組*/
	this.values = function () {
		var arr = [];
		for(var name in items) {
			if(this.has(name)) {
				arr.push(items[name]);
			}
		}

		return arr;
	}

	this.print = function () {
		console.log(this.values());
	}

	/*並集*/
	this.union = function (other_set) {
		var new_set = new Set();
		var values = this.values();
		for(var i=0; i<values.length; ++i) {
			new_set.add(values[i]);
		}

		values = other_set.values();
		for(var i=0; i<values.length; ++i) {
			new_set.add(values[i]);
		}

		return new_set;
	}

	/*交集*/
	this.intersection = function (other_set) {
		var new_set = new Set();
		var values = this.values();
		for(var i=0; i<values.length; ++i) {
			if(other_set.has(values[i])) {
				new_set.add(values[i]);
			}
		}

		return new_set;
	}

	/*差集*/
	this.difference = function (other_set) {
		var new_set = new Set();
		var values = this.values();
		for(var i=0; i<values.length; ++i) {
			if(!other_set.has(values[i])) {
				new_set.add(values[i]);
			}
		}

		return new_set;
	}

	/*判斷是否爲子集*/
	this.isSubset = function (other_set) {
		var other_values = other_set.values();
		var flag = true;
		for(var i=0; i<other_values.length; ++i) {
			if(!this.has(other_values[i])) {
				return false;
			}
		}

		return true;
	}
}


/*測試函數*/
function test(arr) {

	var set = new Set();
	for(var i=0; i<arr.length; ++i) {
		set.add(arr[i]);
	}

	return set;
}

var arr_a = [1, 2, 2, 3, 4];
var set_a = test(arr_a);
console.log(set_a.values());

var arr_b = [1, 3, 5, 9];
var set_b = test(arr_b);
console.log(set_b.values());

var arr_c = [1, 3, 4];
var set_c = test(arr_c);
console.log(set_c.values());

set_a.union(set_b).print();
set_a.intersection(set_b).print();
set_a.difference(set_b).print();
console.log(set_a.isSubset(set_c));
console.log(set_b.isSubset(set_c));