117. 填充每个节点的下一个右侧节点指针 II

var connect = function(root) {
  if (!root) return null

  const nodeArr = [root]

  while (nodeArr.length) {
    const curLine = []
    const length = nodeArr.length

    for (let i = 0; i < length; i++) {
      const res = nodeArr.shift()
      curLine.push(res.val)
      res.left && nodeArr.push(res.left)
      res.right && nodeArr.push(res.right)
      if (length - 1 === i) {
        res.next = null
      } else {
        res.next = nodeArr[0]
      }
    }
  }

  return root
}
console.log(
  connect({
    val: 1,
    left: {
      val: 2,
      left: {
        val: 4,
      },
      right: {
        val: 5,
      },
    },
    right: {
      val: 3,
      right: {
        val: 7,
      },
    },
  })
)