25 A path in a binary tree that sums to a certain value

Input a binary tree and an integer, print out all paths in the binary tree whose sum of node values ​​is the input integer. A path is defined as a path from the root node of the tree down to the nodes passed by the leaf nodes.

 

 

C++:

 1 /*
 2 struct TreeNode {
 3     int val;
 4     struct TreeNode *left;
 5     struct TreeNode *right;
 6     TreeNode(int x) :
 7             val(x), left(NULL), right(NULL) {
 8     }
 9 };*/
10 class Solution {
11 private:
12     vector<vector<int> > res ;
13 public:
14     vector<vector<int> > FindPath(TreeNode* root,int expectNumber) {
15         vector<int> path ;
16         backtracking(root,expectNumber,path) ;
17         return res ;
18     }
19     
20     void backtracking(TreeNode* root,int expectNumber,vector<int> path){
21         if (root == NULL)
22             return ;
23         path.push_back(root->val);
24         expectNumber -= root->val ;
25         if (expectNumber == 0 && root->left == NULL && root->right == NULL){
26             res.push_back(path) ;
27         }else{
28             backtracking(root->left,expectNumber,path) ;
29             backtracking(root->right,expectNumber,path) ;
30         }
31         path.pop_back();
32     }
33 };