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"]

[Thought]

这个主要就是实现题。对树进行深度遍历，在遍历的过程中保存访问节点，当遍历到叶节点的时候，打印出来路径即可。

[Code]

1:  class Solution {  2:  public:  3:    vector
    
      binaryTreePaths(TreeNode* root) {  4:      vector
     
       paths;  5:      vector
      
        nodes;  6:      getAllPaths(root, nodes, paths);       7:      return paths;  8:    }  9:    void getAllPaths(TreeNode* node, vector
       
        & nodes,vector
        
         & paths) {  10:      if(node == NULL) {  11:        return;  12:      }  13:      if(node->left== NULL && node->right == NULL) {  14:        stringstream ss;  15:        for(int i =0; i< nodes.size(); i++) {  16:          ss << nodes[i] << "->";  17:        }  18:        ss << node->val;  19:        paths.push_back(ss.str());  20:        return;  21:      }  22:      nodes.push_back(node->val);  23:      getAllPaths(node->left, nodes, paths);  24:      getAllPaths(node->right, nodes, paths);  25:      nodes.pop_back();  26:    }  27:  };
        
       
      
     
    

Github: