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| 1 | +/** |
| 2 | + * Example: |
| 3 | + * var ti = TreeNode(5) |
| 4 | + * var v = ti.`val` |
| 5 | + * Definition for a binary tree node. |
| 6 | + * class TreeNode(var `val`: Int) { |
| 7 | + * var left: TreeNode? = null |
| 8 | + * var right: TreeNode? = null |
| 9 | + * } |
| 10 | + */ |
| 11 | + //https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree/description |
| 12 | +class Solution { |
| 13 | + fun maxLevelSum(root: TreeNode?): Int { |
| 14 | + var maxSum = Int.MIN_VALUE |
| 15 | + var maxLevel = 0 |
| 16 | + var level = 0 |
| 17 | + val queue: Queue<TreeNode> = LinkedList<TreeNode>() |
| 18 | + queue.add(root) |
| 19 | + |
| 20 | + while(queue.isNotEmpty()){ |
| 21 | + val levelSize = queue.size |
| 22 | + var currentSum = 0 |
| 23 | + for(i in 0 until levelSize){ |
| 24 | + val node = queue.poll() |
| 25 | + currentSum += node?.`val` ?: 0 |
| 26 | + node?.left?.let { |
| 27 | + queue.add(it) |
| 28 | + } |
| 29 | + node?.right?.let { |
| 30 | + queue.add(it) |
| 31 | + } |
| 32 | + } |
| 33 | + level++ |
| 34 | + if(currentSum > maxSum){ |
| 35 | + maxSum = currentSum |
| 36 | + maxLevel = level |
| 37 | + } |
| 38 | + } |
| 39 | + return maxLevel |
| 40 | + } |
| 41 | +} |
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