Valid Parentheses LeetCode

validParentheses.js

/*
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
An input string is valid if:
Open brackets must be closed by the same type of brackets.
Open brackets must be closed in the correct order.
 
Example 1:
Input: s = "()"
Output: true
Example 2:
Input: s = "()[]{}"
Output: true
Example 3:
Input: s = "(]"
Output: false
Example 4:
Input: s = "([)]"
Output: false
Example 5:
Input: s = "{[]}"
Output: true
 
Constraints:
1 <= s.length <= 104
s consists of parentheses only '()[]{}'.
*/

const isValidParantheses = (s) => {
    let map = {
        "(" : ")",
        "{" : "}",
        "[" : "]"
    }
    
    let stack = [];
    
    for (let i = 0; i < s.length; i++) {
        if (s[i] === '(' || s[i] === '{' || s[i] === '[') {
            stack.push(s[i])
        } else {
            let last = stack.pop();
            if (s[i] !== map[last]) {
                return false;   
            }
        }
    }
    
    if (stack.length !== 0) {
        return false;
    }
    
    return true;
}

const s = "()[]{}"
console.log(isValidParantheses(s));