yushman

class Solution {

    val leaves = mutableListOf<Pair<TreeNode, Int>>()
    var depth = 1
    fun deepestLeavesSum(root: TreeNode?): Int {
        if (root == null) return 0
        calcdepth(root)
        val maxdepth = leaves.map { it.second }.maxBy { it }
        return leaves.filter { it.second == maxdepth }.sumBy { it.first.`val` }
    }

yushman

// !!! 
// If you need to handle clicking on the entire element only, you can omit adding View to listener lambda - listener(myModel)
// so in "bind" method you can write only - view.setOnclickListener { listener.invoke(myViewModel) }
class MyAdapter (private val listener: (MyModel, View) -> Unit): RecyclerView.Adapter<MyAdapter.MyViewHolder>{
  val myItemList = listOf<MyModel>()
  //...

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.bind(myItemList[position], listener) //bind listener to position
    }