[LeetCode129]Sum Root to Leaf Numbers
题目:
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
.
分类:Tree DFS
代码:
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 */ 10 class Solution { 11 public: 12 int sumNumbers(TreeNode* root) { 13 return DFS(root,0); 14 } 15 16 int DFS(TreeNode* root, int sum) 17 { 18 if(!root) 19 return 0; 20 int newSum = sum * 10 + root->val; 21 if(!root->left && !root->right) 22 return newSum; 23 return DFS(root->left,newSum) + DFS(root->right,newSum); 24 } 25 };