二叉树中和为某一值的路径

 1 import java.util.ArrayList;
 2 /**
 3 public class TreeNode {
 4     int val = 0;
 5     TreeNode left = null;
 6     TreeNode right = null;
 7 
 8     public TreeNode(int val) {
 9         this.val = val;
10 
11     }
12 
13 }
14 */
15 public class Solution {
16     public void dfs(ArrayList<ArrayList<Integer>>ans, ArrayList<Integer>temp, TreeNode p, int target){
17         temp.add(p.val);
18         if (p.left == null && p.right == null) {
19             if (target == p.val) {
20           
21                 ans.add(new ArrayList<>(temp));
22                 
23             }
24             temp.remove(temp.size() - 1);
25             return;
26         }
27         if (p.left != null)
28         dfs(ans, temp, p.left, target - p.val);
29         if (p.right != null)
30         dfs(ans, temp, p.right, target - p.val);
31         temp.remove(temp.size() - 1);
32         
33     }
34     public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target) {
35         ArrayList<ArrayList<Integer>> ans = new ArrayList<>();
36         ArrayList<Integer> temp = new ArrayList<>();
37         if (root == null) {
38             return ans;    
39         }
40         dfs(ans, temp, root, target);
41         return ans;
42     }
43 }