js集合set類的實現

js集合set類的實現

/*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;//求並集
    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。屬於集合cis,不屬於集合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());