[LeetCode][JavaScript]Valid Parentheses

Valid Parentheses

Given a string containing just the characters

'('

,

')'

,

'{'

,

'}'

,

'['

and

']'

, determine if the input string is valid.

The brackets must close in the correct order,

"()"

and

"()[]{}"

are all valid but

"(]"

and

"([)]"

are not.

https://leetcode.com/problems/valid-parentheses/

水题好愉快。

/**
* @param {string} s
* @return {boolean}
*/
var isValid = function(s) {
var stack = [];
function brackets(left, right){
if(left === '(' && right === ')'){
return true;
}else if(left === '[' && right === ']'){
return true;
}else if(left === '{' && right === '}'){
return true;
}
return false;
}
var top = null;
for(var i in s){
if(/[\({\[]/.test(s[i])){
stack.push(s[i]);
}else{
if(stack.length > 0){
top = stack.pop();
if(!brackets(top, s[i])){
return false;
}
}else{
return false;
}
}
}

if(stack.length !== 0){
return false;
}
return true;
};