/*js集合set類的實現*/
function Set() {
 this.dataStore = [];
 this.add = add;//新增元素
 this.remove = remove;//刪除元素
 this.size = size;//集合的元素個數
 this.union = union;//求并集
 this.contains = contains;//判斷一個集合中是否包含某個元素
 this.intersect = intersect;//交集
 this.subset = subset;//判斷一個集合是否是另一個的子集
 this.difference = difference;//求補集
 this.show = show;//將集合元素顯示出來
}
function add(data) {
 if (this.dataStore.indexOf(data) < 0) {
 this.dataStore.push(data);
 return true;
 }
 else {
 return false;
 }
}
function remove(data) {
 var pos = this.dataStore.indexOf(data);
 if (pos > -1) {
 this.dataStore.splice(pos,1);
 return true;
 }
 else {
 return false;
 }
}
function size() {
 return this.dataStore.length;
}
function show() {
 return "[" + this.dataStore + "]";
}
function contains(data) {
 if (this.dataStore.indexOf(data) > -1) {
 return true;
 }
 else {
 return false;
 }
}
function union(set) {
 var tempSet = new Set();
 for (var i = 0; i < this.dataStore.length; ++i) {
 tempSet.add(this.dataStore[i]);
 }
 for (var i = 0; i < set.dataStore.length; ++i) {
 if (!tempSet.contains(set.dataStore[i])) {
 tempSet.dataStore.push(set.dataStore[i]);
 }
 }
 return tempSet;
}
function intersect(set) {
 var tempSet = new Set();
 for (var i = 0; i < this.dataStore.length; ++i) {
 if (set.contains(this.dataStore[i])) {
 tempSet.add(this.dataStore[i]);
 }
 }
 return tempSet;
}
function subset(set) {
 if (this.size() > set.size()) {
 return false;
 }
 else {
 for(var member in this.dataStore) {
 if (!set.contains(member)) {
 return false;
 }
 }
 }
 return true;
}
function difference(set) {
 var tempSet = new Set();
 for (var i = 0; i < this.dataStore.length; ++i) {
 if (!set.contains(this.dataStore[i])) {
 tempSet.add(this.dataStore[i]);
 }
 }
 return tempSet;
}
/*測試例子：求補集。屬于集合cis,不屬于集合it*/
var cis = new Set();
var it = new Set();
cis.add("Clayton");
cis.add("Jennifer");
cis.add("Danny");
it.add("Bryan");
it.add("Clayton");
it.add("Jennifer");
var diff = new Set();
diff = cis.difference(it);
console.log(cis.show() + " difference " + it.show() + " -> " + diff.show());