leetcode@ [129] Sum Root to Leaf Numbers (DFS)
https://leetcode.com/problems/sum-root-to-leaf-numbers/
Given a binary tree containing digits from 0-9
only, 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 = 12 + 13 = 25
.
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
/** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: void travel(vector<vector<int> >& nums, vector<int>& load, TreeNode* root) { if(!(root->left) && !(root->right)) { nums.push_back(load); return; } if(root->left) { load.push_back(root->left->val); travel(nums, load, root->left); load.pop_back(); } if(root->right) { load.push_back(root->right->val); travel(nums, load, root->right); load.pop_back(); } } int sumNumbers(TreeNode* root) { if(root == NULL) return 0; vector<vector<int> > nums; vector<int> load; int res = 0; load.push_back(root->val); travel(nums, load, root); for(int i=0; i<nums.size(); ++i) { int rhs = 0; for(int j=0; j<nums[i].size(); ++j) { rhs = rhs * 10 + nums[i][j]; } res += rhs; } return res; } };