Sets Back

A set is a collection of unique elements, in which elements are also called members.

Sets Definition

A set containing no members is called the empty set. The universe is the set of all possible members.

If two sets contain exactly the same members, we consider them as equal.

A set is consider a subset of another set if all the members of the preceding set are contained in the following one.

function Set() {
    this.dataStore = [];

    /** methods */
    this.add = add;
    this.remove = remove;
    this.show = show;

    /** set operations */
    this.size = size;
    this.union = union;
    this.interset = interset;
    this.subset = subset;
    this.difference = difference;
}

function add(data) {
    if (this.dataStore.indexOf(data) < 0) {
        this.dataStore.add(data);
        return true;
    } else {
        return false;
    }
}

function remove(data) {
    var index = this.dataStore.indexOf(data);

    if (index > 0) {
        this.dataStore.slice(index, 1);
        return true;
    } else {
        return false;
    }
}

function show() {
    return this.dataStore;
}

Set Operations

function contain(data) {
    if (this.data.indexOf(data) < 0) {
        return false;
    } else {
        return true;
    }
}

function size() {
    return this.dataStore.length;
}

function union(set) {
    var tmpSet = new Set();
    var store = this.dataStore;
    var storeLen = store.length;

    var setStore = set.dataStore;
    var setStoreLen = setStore.length;

    for (var i = 0; i < storeLen; i++) {
        tmpSet.add(store[i]);
    }

    for (var i = 0; i < setStoreLen; i++) {
        tmpSet.add(setStore[i]);
    }

    return tmpSet;
}

function intersect(set) {
    var tmpSet = new Set();
    var setStore = set.dataStore;
    var setStoreLen = setStore.length;

    for (var i = 0; i < setStoreLen; i++) {
        if (this.contain(setStore[i])) {
            tmpSet.add(setStore[i]);
        }
    }

    return tmpSet;
}

/** check whether it's a subset of the given set */
function subset(set) {
    if (this.size() > set.size()) {
        return false;
    } else {
        var store = this.dataStore;
        var storeLen = store.length;

        for (var i = 0; i < storeLen; i++) {
            if (!set.contain(store[i])) {
                return false;
            }
        }

        return true;
    }
}

function difference(set) {
    var tmpSet = new Set();
    var store = this.dataStore;
    var storeLen = store.length;

    for (var i = 0; i < storeLen; i++) {
        if (!set.contain(store[i])) {
            tmpSet.add(store[i]);
        }
    }

    return tmpSet;
}