Valid parentheses

Given a only include a ‘(‘,’) ‘, ‘{‘,’} ‘, ‘/’, ‘ ‘the string s, determine whether a string is effective.

A valid string must meet the following requirements:

1. An open parenthesis must be closed with a close parenthesis of the same type.
2. The left parentheses must be closed in the correct order.

Personal answer key

var isValid = function(s) {
    const obj = {
        '{':'} '.'(':') '.'[':'] '
    }
    let arr = [];
    for(let i = 0; i<s.length; i++){if(s[i]==='('||s[i]==='{'||s[i]==='['){
            arr.push(s[i]);
        }else if(s[i]! ==obj[arr[arr.length-1]]) {return false;
        }else{ arr.pop(s[i]); }}return arr.length === 0;
};
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Analysis of the

【 Concept of stack 】

• An operation that matches a class can define a one-to-one object.
• Arr. Length === 0 itself returns a Boolean value.