Given a string that may consist of opening and closing parentheses, your task is to check whether or not the string contains valid parenthesization.

valid-parentheses.js

function isValid(s) {
  const stack = [];

  const open = ["(", "[", "{"];
  const closing = [")", "]", "}"];

  for (const char of s) {
    const index = closing.indexOf(char);
    if (index !== -1 && stack[stack.length - 1] === open[index]) {
      stack.pop();
    } else {
      stack.push(char);
    }
  }

  return stack.length === 0;
}

export {
  isValid
};

// tc: O(n) 
// sc: O(n)