Data Structure Binary Tree: Check if a given Binary Tree is SumTree

 1 #include <iostream>
 2 #include <vector>
 3 #include <algorithm>
 4 #include <queue>
 5 #include <stack>
 6 #include <string>
 7 #include <fstream>
 8 using namespace std;
 9 
10 struct node {
11     int data;
12     struct node *left, *right;
13     node() : data(0), left(NULL), right(NULL) { }
14     node(int d) : data(d), left(NULL), right(NULL) { }
15 };
16 
17 bool isleaf(node *root) {
18     return !root->left && !root->right;
19 }
20 
21 bool issumtree(node *root) {
22     if (!root || isleaf(root)) return true;
23     int l = 0;
24     int r = 0;
25     if (root->left == NULL) l = 0;
26     else if (isleaf(root->left)) l = root->left->data;
27     else l = 2 * root->left->data;
28     if (root->right == NULL) r = 0;
29     else if (isleaf(root->right)) r = root->right->data;
30     else r = 2 * root->right->data;
31     return root->data == l + r && issumtree(root->left) && issumtree(root->right);
32 }
33 
34 int main() {
35     node *root = new node(26);
36     root->left = new node(10);
37     root->right = new node(3);
38     root->left->left = new node(4);
39     root->left->right = new node(6);
40     root->right->right = new node(3);
41     if (issumtree(root)) cout << "yes" << endl;
42     else cout << "NO" << endl;
43     return 0;
44 }