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. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public List
     
       paths;    public List
      
        path;    public List
       
         binaryTreePaths(TreeNode root) {        paths = new ArrayList
        
         ();        path = new ArrayList
         
          ();        getAllPath(root);                return paths;    }        public void getAllPath(TreeNode node) {            //       1    //     /   \    //    2     3    ["1->2->5", "1->3"]    //     \    //      5            if(node == null) {            return ;        }        path.add(node.val);        if(node.left==null && node.right==null) {            StringBuilder onePath = new StringBuilder();            for(int i=0; i
          
           "); onePath.append(path.get(i)); } paths.add(onePath.toString()); } getAllPath(node.left); getAllPath(node.right); path.remove(path.size() - 1); }}