题目连接

  

 Binary Tree Paths

Description

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:

$["1−>2−>5","1−>3"]$

/** * 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:	vector
     
       binaryTreePaths(TreeNode* root) {		ans.clear();		if (!root) return ans;		dfs(root, "");		return ans;	}private:	vector
      
        ans;	void dfs(TreeNode *x, string ret) {		if (!x) return;		if (!x->left && !x->right) {			ans.push_back(ret + to_string(x->val));			return;		}		dfs(x->left, ret + to_string(x->val) + "->");		dfs(x->right, ret + to_string(x->val) + "->");	}};