1 import java.util.ArrayList;
 2 import java.util.Stack;
 3 public class Solution {
 4     public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,
 5             int target) {
 6         ArrayList<ArrayList<Integer>> pathList=
 7                 new ArrayList<ArrayList<Integer>>();
 8         if(root==null)
 9             return pathList;
10         Stack<Integer> stack=new Stack<Integer>();
11         FindPath(root,target,stack,pathList );
12         return pathList;
13          
14     }
15     private void FindPath(TreeNode root, int target,
16             Stack<Integer> path,
17             ArrayList<ArrayList<Integer>> pathList) {
18         if(root==null)
19             return;
20         if(root.left==null&&root.right==null){
21             if(root.val==target){
22                 ArrayList<Integer> list=
23                         new ArrayList<Integer>();
24                 for(int i:path){
25                     list.add(new Integer(i));
26                 }
27                 list.add(new Integer(root.val));
28                 pathList.add(list);
29             }
30         }
31         else{
32             path.push(new Integer(root.val));
33             FindPath(root.left, target-root.val, path, pathList);
34             FindPath(root.right, target-root.val, path,  pathList);
35             path.pop();
36         }
37          
38     }
39 }