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function matches(open, close)

{

    var opens = "([{",

        closers = ")]}";

    return opens.indexOf(open) == closers.indexOf(close);

}



function parenthesesChecker(symbols)

{

    var stack = new Stack();

    var balanced = true;

    var index = 0;

    var symbol, top;



    while (index < symbols.length && balanced)

    {

        symbol = symbols.charAt(index);

        if (symbol == '(' || symbol == '[' || symbol == '{')

        {

            stack.push(symbol);

        }

        else 

        {

            if (stack.isEmpty())

            {

                balanced = false;

            }

            else 

            {

                top = stack.pop();

                if ( !matches(top, symbol) )

                {

                    balanced = false;

                }

            }

        }



        index++;

    }



    if (balanced && stack.isEmpty())

    {

        return true;

    }

    

    return false;

}



console.log(parenthesesChecker('{{([][])}()}'));

console.log(parenthesesChecker('[{()]'));





function Stack() 

{

    var items = [];



    this.push = function(element) { items.push(element); };



    this.pop = function() { return items.pop(); };



    this.peek = function() { return items[items.length-1]; };



    this.isEmpty = function() { return items.length == 0; };



    this.size = function() { return items.length; };



    this.clear = function() { items = []; };



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



    this.toString = function() { return items.toString(); };

}