20.js

/** ------------------------------------------------------------------------------
 * 
 * 2023-04-10
 * Valid Parentheses
 * https://leetcode.com/problems/valid-parentheses/
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {string} s
 * @return {boolean}
 */
var isValid = function (str) {
  if (str.length <= 1 || str.length % 2 !== 0) return false

  const stack = []
  for (const s of str) {
    if (mapping[s]) {
      stack.push(mapping[s])
    } else {
      const last = stack.pop()
      if (last !== s) return false
    }
  }

  return stack.length === 0
}

const mapping = {
  "(": ")",
  "{": "}",
  "[": "]",
}