Javascript Array Comparison

Question

I saw one interview question .(i.e)
I have one array inside a function

function validate(){
    var array=["(","{","[","]","}",")"];
 }

Also i have one input field with submit button

<body>
<input type="text" name="equation" id="equation">
<input type="submit" name="check" value="check" onclick="validate();">
</body>

Now my doubt is when I enter input data as {()} it should display valid data in an alert.When I enter input data like {()}] it should display as invalid data.Which means for unbalanced input it should display invalid message.For that I need to compare array elements within an array.

How to do it?

This it not clear. What should the function validate do ? What have you tried ? — Weedoze
– Weedoze, Commented Jan 11, 2017 at 9:31
` var a=document.getElementById('equation').value; var y=eval(a); alert("your answer is"+y);` <br>i just tried using eval.But this is not my question i need compare array values only unbalanced symbols .I don't know how to do it. — user7397787
– user7397787, Commented Jan 11, 2017 at 9:33
is this only for braces or there can be other input as well? — Mustafa Mamun
– Mustafa Mamun, Commented Jan 11, 2017 at 9:40
@MustafaMamun we can give input like [(x+y)*(y-x)] but it should check only braces value doesn't matter. — user7397787
– user7397787, Commented Jan 11, 2017 at 9:47

Nina Scholz · Accepted Answer · 2017-01-11 11:11:07Z

1

You could save the opened brackets and delete the last if the corespondent bracket is found. At last, check if the open bracket array is empty.

function validate(s) {
    var open = [],
        brackets = { '(': 1, '{': 2, '[': 3, ']': -3, '}': -2, ')': -1 };

    return s.split('').every(function (a) {
        if (!brackets[a]) {
           return true;
        }
        if (brackets[a] > 0) {
            open.push(-brackets[a]);
            return true;
        }
        if (open[open.length - 1] ===  brackets[a] ) {
            open.pop();
            return true;
        }
    }) && open.length === 0;
 }

console.log(validate('([()()])'));
console.log(validate('(a+2)*4'));
console.log(validate(']'));

edited Jan 11, 2017 at 11:11

answered Jan 11, 2017 at 10:03

Nina Scholz

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