sum-root-to-leaf-numbers——dfs
Given a binary tree containing digits from0-9only, each root-to-leaf path could represent a number.
An example is the root-to-leaf path1->2->3which represents the number123.
Find the total sum of all root-to-leaf numbers.
For example,
1 / \ 2 3
The root-to-leaf path1->2represents the number12.
The root-to-leaf path1->3represents the number13.
Return the sum = 12 + 13 =25.
1 /** 2 * Definition for binary tree 3 * struct TreeNode { 4 * int val; 5 * TreeNode *left; 6 * TreeNode *right; 7 * TreeNode(int x) : val(x), left(NULL), right(NULL) {} 8 * }; 9 */ 10 class Solution { 11 public: 12 int sumNumbers(TreeNode *root) { 13 if(root==NULL) 14 return 0; 15 res=0; 16 dfs(root,0); 17 return res; 18 } 19 void dfs(TreeNode *root,int num){ 20 if(root!=NULL){ 21 num=num*10+root->val; 22 } 23 if(root->left==NULL&&root->right==NULL){ 24 res+=num; 25 } 26 if(root->left!=NULL){ 27 dfs(root->left,num); 28 } 29 if(root->right!=NULL){ 30 dfs(root->right,num); 31 } 32 } 33 int res; 34 };
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