(leetcode)Binary Tree Paths

Given a binary tree, return all root-to-leaf paths.

For example, given the following binary tree:

 

   1
 /   \
2     3
 \
  5

 

All root-to-leaf paths are:

["1->2->5", "1->3"]
 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     vector<string> binaryTreePaths(TreeNode* root) {
13         if(!root) return vector<string>();
14         vector<string> res;
15         string s;
16         DFS(root,to_string(root->val),res);
17         return res;
18         
19     }
20     void DFS(TreeNode* root,string s,vector<string>& res)
21     {
22         if(!root->left && !root->right) res.push_back(s);
23         if(root->left) DFS(root->left,s+"->"+to_string(root->left->val),res);
24         if(root->right) DFS(root->right,s+"->"+to_string(root->right->val),res);
25     }
26 };

 

posted @ 2015-08-19 14:46  sunalive  Views(146)  Comments(0)    收藏  举报