1 package data.structure.exercise;
 2 
 3 import java.util.LinkedList;
 4 
 5 
 6 public class BinaryTree extends BinarySearchTree{
 7     
 8     LinkedList<TreeNode> pathStack = new LinkedList<TreeNode>();
 9     
10     public BinaryTree(int root){
11         
12         super(root);
13     }
14 
15     
16     public void findPathSum(int sum){
17         if(this.getRoot() == null){
18             return;
19         }
20         dfs(this.getRoot(), sum);
21     }
22     
23     private void dfs(TreeNode node, int current){
24         if(node == null){
25             return;
26         }
27         
28         pathStack.push(node);;
29         
30         if(node.getLnode() == null && node.getRnode() == null){
31             //being a path and calculate the sum
32             if(current == node.getValue()){
33                 printPath(pathStack);
34             }
35         }else{
36             //traverse left node
37             if(node.getLnode() !=null){
38                 
39                 dfs(node.getLnode(), current - node.getValue());
40             }
41             
42             //traverse right node
43             if(node.getRnode() !=null){
44                 dfs(node.getRnode(), current - node.getValue());
45             }
46         }
47         pathStack.pop();
48         
49     }
50     
51     private void printPath(LinkedList<TreeNode> pathStack){
52         for(TreeNode node:pathStack){
53             System.out.print(node.toValueString()+"=");
54         }
55         System.out.println();
56     }
57     
58     public static void main(String[] args){
59         BinaryTree tree = new BinaryTree(10);
60         tree.insert(5);
61         tree.insert(12);
62         tree.insert(4);
63         tree.insert(7);
64 
65         
66         System.out.println("root.left: "+ tree.getRoot().getLnode().toString());
67 
68         tree.findPathSum(22);
69     }
70 }