snippets

function isValid(s) {
  const stack = [];
  const pairs = { ")": "(", "]": "[", "}": "{" };
  for (const c of s) {
    if (c in pairs) {
      if (stack.pop() !== pairs[c]) return false;
    } else {
      stack.push(c);
    }
  }
  return stack.length === 0;
}