[lintcode easy]Binary Tree Paths

Binary Tree Paths

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

Example

Given the following binary tree:

   1
 /   2     3
   5

All root-to-leaf paths are:

[
  "1->2->5",
  "1->3"
]

/**
 * Definition of TreeNode:
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left, right;
 *     public TreeNode(int val) {
 *         this.val = val;
 *         this.left = this.right = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param root the root of the binary tree
     * @return all root-to-leaf paths
     */
     List<String> list=new ArrayList<String>();
    public List<String> binaryTreePaths(TreeNode root) {
        // Write your code here

       if(root!=null)
       {
           getPaths(root,String.valueOf(root.val));
       }

       return list;
    }

    public void getPaths(TreeNode n, String path)
    {
        if(n.left==null && n.right==null)
        {
            list.add(path);
        }

        if(n.left!=null)
        {
            getPaths(n.left,path+"->"+n.left.val);
        }

        if(n.right!=null)
        {
            getPaths(n.right,path+"->"+n.right.val);
        }
    }
}