/**
 *
 * Ashish Patel
 * e: ashishsushilPatel@gmail.com
 * w: https://ashish.me
 *
 */

function TreeNode(val) {
  this.val = val
  this.left = this.right = null
}

const invertBinaryTree = root => {
  if (root == null) {
    return null
  }
  let traverse = root => {
    if (!root.left && !root.right) {
      return
    }
    let temp = root.left
    root.left = root.right
    root.right = temp
    root.left && traverse(root.left)
    root.right && traverse(root.right)
  }
  traverse(root)
  return root
}

test('invertBinaryTree', () => {
  const t1 = new TreeNode(4)
  t1.right = new TreeNode(7)
  t1.left = new TreeNode(2)
  t1.left.left = new TreeNode(1)
  t1.left.right = new TreeNode(3)
  t1.right.left = new TreeNode(6)
  t1.right.right = new TreeNode(9)

  const t2 = new TreeNode(4)
  t2.right = new TreeNode(2)
  t2.left = new TreeNode(7)
  t2.left.left = new TreeNode(9)
  t2.left.right = new TreeNode(6)
  t2.right.left = new TreeNode(3)
  t2.right.right = new TreeNode(1)

  expect(invertBinaryTree(t1)).toEqual(t2)
})