在二叉树中找出和为某一值的所有路径

 1 #include <iostream>
 2 #include <sstream>
 3 #include <vector>
 4 #include <stdlib.h>
 5 
 6 using namespace std;
 7 
 8 struct TreeNode
 9 {
10     int val;
11     TreeNode *left, *right;
12     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
13 };
14 
15 void creatTree(TreeNode *&root, vector<int>& a, int i, int len)
16 {
17     if (i >= len)
18         return;
19     root = new TreeNode(a[i]);
20     creatTree(root->left, a, 2 * i + 1, len);
21     creatTree(root->right,a, 2 * i + 2, len);
22 }
23 
24 void inorderTraversal(TreeNode* root)
25 {
26     if (root)
27     {
28         cout << root->val << " ";
29         inorderTraversal(root->left);
30         inorderTraversal(root->right);
31     }
32 }
33 
34 vector<int> vec;
35 int sum = 0;
36 bool isCoutBlank = false;
37 bool isFind = false;
38 void pathTree(TreeNode*& root, int target)
39 {
40     sum += root->val;
41     vec.push_back(root->val);
42     if (sum == target && !root->left && !root->right)
43     {
44         isFind = true;
45         if(isCoutBlank)
46             cout << endl;
47         isCoutBlank = true;
48         for (int i = 0; i < vec.size() - 1; ++i)
49         {
50             cout << vec[i]<< ",";
51         }
52         cout << vec[vec.size() - 1];
53     }
54     if (root->left)
55         pathTree(root->left, target);
56     if (root->right)
57         pathTree(root->right, target);
58     sum -= root->val;
59     vec.pop_back();
60 }
61 
62 
63 int main()
64 {
65     TreeNode* root = nullptr;
66     int target;
67     cin >> target;
68     string val;
69     cin >> val;
70     string temp;
71     stringstream ss(val);
72     int node;
73     vector<int> nodes;
74     while (!ss.eof())
75     {
76         getline(ss, temp, ‘,‘);
77         stringstream stmp;
78         stmp << temp;
79         stmp >> node;
80         nodes.push_back(node);
81     }
82     creatTree(root, nodes, 0, nodes.size());
83     pathTree(root,target);
84     if (!isFind)
85         cout << "error";
86 }