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48 lines
1.4 KiB
Markdown
Executable File
48 lines
1.4 KiB
Markdown
Executable File
# [129. Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/)
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## 题目
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Given a binary tree containing digits from `0-9` only, each root-to-leaf path could represent a number.
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An example is the root-to-leaf path `1->2->3` which represents the number `123`.
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Find the total sum of all root-to-leaf numbers.
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**Note:** A leaf is a node with no children.
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**Example:**
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Input: [1,2,3]
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1
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/ \
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2 3
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Output: 25
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Explanation:
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The root-to-leaf path 1->2 represents the number 12.
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The root-to-leaf path 1->3 represents the number 13.
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Therefore, sum = 12 + 13 = 25.
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**Example 2:**
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Input: [4,9,0,5,1]
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4
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/ \
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9 0
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/ \
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5 1
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Output: 1026
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Explanation:
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The root-to-leaf path 4->9->5 represents the number 495.
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The root-to-leaf path 4->9->1 represents the number 491.
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The root-to-leaf path 4->0 represents the number 40.
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Therefore, sum = 495 + 491 + 40 = 1026.
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## 题目大意
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给定一个二叉树，它的每个结点都存放一个 0-9 的数字，每条从根到叶子节点的路径都代表一个数字。例如，从根到叶子节点路径 1->2->3 代表数字 123。计算从根到叶子节点生成的所有数字之和。说明: 叶子节点是指没有子节点的节点。
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## 解题思路
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- 运用前序遍历的思想，当从根节点出发一直加到叶子节点，每个叶子节点汇总一次。 |