[Leetcode] Sum Root to Leaf Numbers

Title Description: (link)

Given a binary tree containing digits from only 0-9 , each root-to-leaf path could represent a number.

An example is the Root-to-leaf path 1->2->3 which represents the number 123 .

Find The total sum of all root-to-leaf numbers.

For example,

    1   /   2   3

The Root-to-leaf path 1->2 represents the number 12 .
The Root-to-leaf path 1->3 represents the number 13 .

Return the sum = + = 25 .

Problem Solving Ideas:

Depth-first search, traversing the path of all root nodes to the leaf nodes.

1 /**2 * Definition for a binary tree node.3 * struct TreeNode {4 * int val;5 * TreeNode *left;6 * TreeNode *right;7 * TreeNode (int x): Val (x), left (null), right (null) {}8  * };9  */Ten classSolution { One  Public: A     intSumnumbers (treenode*root) { -         returnSumnumbers (Root,0); -     } the Private: -     intSumnumbers (TreeNode *root,intsum) { -         if(Root = = nullptr)return 0; -sum = SUM *Ten+ root->Val; +         if(Root->left = = nullptr && Root->right = =nullptr) { -             returnsum; +         } A          at         returnSumnumbers (Root->left, sum) + sumnumbers (root->Right , sum); -     } -};

[Leetcode] Sum Root to Leaf Numbers