題目：

輸入一顆二叉樹和一個整數，打印出二叉樹中結點值的和為輸入整數的所有路徑。
從樹的根結點開始往下一直到葉結點所經過的結點形成一條路徑。

解答：

 1 import java.util.*;
 2 
 3 public class Solution {
 4     public static void main(String[] args) {
 5         BinaryTreeNode root=new BinaryTreeNode(10);
 6         BinaryTreeNode node1=new BinaryTreeNode(5);
 7         BinaryTreeNode node2=new
 
 BinaryTreeNode(4);
 8         BinaryTreeNode node3=new BinaryTreeNode(7);
 9         BinaryTreeNode node4=new BinaryTreeNode(12);
10         root.setLchildNode(node1);root.setRchildNode(node4);
11         node1.setLchildNode(node2);node1.setRchildNode(node3);
12         findPath(root,22);
13     }
14
 
 
15     private static void findPath(BinaryTreeNode root, int i) {
16         if(root == null) {
17             return;
18         }
19 
20         Stack<Integer> stack  = new Stack<Integer>();
21         int currentSum = 0;
22         findPath(root, i, stack, currentSum);
23     }
24 
25
 
     private static void findPath(BinaryTreeNode root, int i, Stack<Integer> stack, int currentSum) {
26         currentSum = currentSum + root.getData();
27         stack.push(root.getData());
28 
29         if(root.getLchildNode() == null && root.getRchildNode() == null) {
30             if(currentSum == i) {
31                 System.out.println("find path");
32                 for(int path:stack) {
33                     System.out.println(path + " ");
34                 }
35             }
36         }
37 
38         if(root.getLchildNode() != null) {
39             findPath(root.getLchildNode(), i, stack, currentSum);
40         }
41 
42         if(root.getRchildNode() != null) {
43             findPath(root.getRchildNode(), i, stack, currentSum);
44         }
45 
46         stack.pop();
47     }
48 }

輸入一顆二叉樹和一個整數，打印出二叉樹中結點值的和為輸入整數的所有路徑