[Algorithm] 20 week(5.30 ~ 6.5) 3/3

226. Invert Binary Tree

var invertTree = function(root) {
  if (!root) {
    return root;
  }

  invertFunc(root, root.left, root.right);
  return root;
};

  function invertFunc(root, left, right) {
    if (!root) {
      return;
    }
    let temp = right;
    root.right = left;
    root.left = temp;
    if (root.left) {
      invertFunc(root.left, root.left.left, root.left.right);
    }
    if (root.right) {
      invertFunc(root.right, root.right.left, root.right.right);
    }
  }