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58 lines
1.3 KiB
Markdown
58 lines
1.3 KiB
Markdown
# [1302. Deepest Leaves Sum](https://leetcode.com/problems/deepest-leaves-sum/)
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## 题目
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Given a binary tree, return the sum of values of its deepest leaves.
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**Example 1**:
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```
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Input: root = [1,2,3,4,5,null,6,7,null,null,null,null,8]
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Output: 15
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```
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**Constraints**:
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- The number of nodes in the tree is between `1` and `10^4`.
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- The value of nodes is between `1` and `100`.
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## 题目大意
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给你一棵二叉树，请你返回层数最深的叶子节点的和。
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提示：
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- 树中节点数目在 1 到 10^4 之间。
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- 每个节点的值在 1 到 100 之间。
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## 解题思路
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- 给你一棵二叉树，请你返回层数最深的叶子节点的和。
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- 这一题不难，DFS 遍历把最底层的叶子节点和都加起来即可。
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## 代码
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```go
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func deepestLeavesSum(root *TreeNode) int {
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maxLevel, sum := 0, 0
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dfsDeepestLeavesSum(root, 0, &maxLevel, &sum)
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return sum
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}
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func dfsDeepestLeavesSum(root *TreeNode, level int, maxLevel, sum *int) {
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if root == nil {
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return
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}
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if level > *maxLevel {
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*maxLevel, *sum = level, root.Val
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} else if level == *maxLevel {
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*sum += root.Val
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}
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dfsDeepestLeavesSum(root.Left, level+1, maxLevel, sum)
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dfsDeepestLeavesSum(root.Right, level+1, maxLevel, sum)
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}
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``` |