/*
    Given a string of open and close parentheses return the count of
    parentheses need to make the string a valid string of parentheses.
    You are not permitted to rearrange valid parentheses to make a
    valid string.

    Examples:
        - '()' => 0
        - ')(' => 2
        - '()) => 1
*/

const makeValidParentheses = (str) => {
  let unmatchedOpen = 0;
  let unmatchedClose = 0;
  for (const char of str) {
    //  Increment the open counter
    if (char === '(') {
      unmatchedOpen += 1;
    }

    if (char === ')') {
      //  Decrement the open counter
      unmatchedOpen -= 1;
      if (unmatchedOpen < 0) {
        //  If the open count is negative there is an unmatched close
        unmatchedClose += 1;
        //  After accounting for the unmatched close set open back to 0
        unmatchedOpen = 0;
      }
    }
  }

  return unmatchedOpen + unmatchedClose;
};

//  Tests
const parentheses = [
  { input: '', output: 0 },
  { input: '(()', output: 1 },
  { input: '())', output: 1 },
  { input: '()()', output: 0 },
  { input: '()(()', output: 1 },
  { input: '())()', output: 1 },
  { input: '())(()', output: 2 },
  { input: '((()))', output: 0 },
];

parentheses.forEach(({ input, output }) => {
  console.log(`Input:\t${input}`);
  console.log(`Expected:\t${output}`);
  console.log(`  Actual:\t${makeValidParentheses(input)}`);
  console.log();
});