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

// Related Topics: String, Stack

// Difficulty: Easy

/*

Initial thoughts:

Creating a lookup table for all the types of parentheses and

using a stack we touch every element of the input string and

if it's an opening parenthes push it on the stack and if its

a closing parenthes we pop one from the stack checking if it's

a valid counterpart for the current parenthes.

At the end, the stack must be empty

Time complexity: O(n) where n === s.length

Space complexity: O(n) where n === s.length

*/

/**

* @param {string} s

* @return {boolean}

*/

const isValid = s => {

const stack = [];

for (let i = 0; i < s.length; i++) {

const temp = s[i];

if (opening[temp]) stack.push(temp);

else if (stack.pop() !== closing[temp]) return false;

}

return stack.length === 0;

};

const opening = { '(': ')', '[': ']', '{': '}' };

const closing = { ')': '(', ']': '[', '}': '{' };