1302. Deepest Leaves Sum

1302. Deepest Leaves Sum #

题目 #

Given a binary tree, return the sum of values of its deepest leaves.

Example 1:

https://assets.leetcode.com/uploads/2019/07/31/1483_ex1.png

Input: root = [1,2,3,4,5,null,6,7,null,null,null,null,8]
Output: 15

Constraints:

  • The number of nodes in the tree is between 1 and 10^4.
  • The value of nodes is between 1 and 100.

题目大意 #

给你一棵二叉树,请你返回层数最深的叶子节点的和。

提示:

  • 树中节点数目在 1 到 10^4 之间。
  • 每个节点的值在 1 到 100 之间。

解题思路 #

  • 给你一棵二叉树,请你返回层数最深的叶子节点的和。
  • 这一题不难,DFS 遍历把最底层的叶子节点和都加起来即可。

代码 #

func deepestLeavesSum(root *TreeNode) int {
	maxLevel, sum := 0, 0
	dfsDeepestLeavesSum(root, 0, &maxLevel, &sum)
	return sum
}

func dfsDeepestLeavesSum(root *TreeNode, level int, maxLevel, sum *int) {
	if root == nil {
		return
	}
	if level > *maxLevel {
		*maxLevel, *sum = level, root.Val
	} else if level == *maxLevel {
		*sum += root.Val
	}
	dfsDeepestLeavesSum(root.Left, level+1, maxLevel, sum)
	dfsDeepestLeavesSum(root.Right, level+1, maxLevel, sum)
}

⬅️上一页

下一页➡️

Calendar Sep 6, 2020
Edit Edit this page
本站总访问量:  次 您是本站第  位访问者