package q1161

import "math"

type TreeNode struct {
	Val   int
	Left  *TreeNode
	Right *TreeNode
}

func maxLevelSum(root *TreeNode) int {
	type qElem struct {
		node  *TreeNode
		level int
	}
	queue := make([]qElem, 0, 256)
	queue = append(queue, qElem{root, 1})

	maxSum, maxLvl := math.MinInt, 0
	sum, lvl := 0, 1
	for ; len(queue) > 0; queue = queue[1:] {
		cur := &queue[0]
		if cur.level != lvl {
			if sum > maxSum {
				maxSum, maxLvl = sum, lvl
			}
			sum, lvl = 0, cur.level
		}
		sum += cur.node.Val
		if cur.node.Left != nil {
			queue = append(queue, qElem{cur.node.Left, cur.level + 1})
		}
		if cur.node.Right != nil {
			queue = append(queue, qElem{cur.node.Right, cur.level + 1})
		}
	}
	if sum > maxSum {
		return lvl
	}
	return maxLvl
}

var _ = maxLevelSum