Data Structure Binary Tree: Largest Independent Set Problem

http://www.geeksforgeeks.org/largest-independent-set-problem/

 1 #include <iostream>
 2 #include <vector>
 3 #include <algorithm>
 4 #include <queue>
 5 #include <stack>
 6 #include <string>
 7 #include <fstream>
 8 #include <map>
 9 using namespace std;
10 
11 struct node {
12     int data;
13     struct node *left, *right;
14     node() : data(0), left(NULL), right(NULL) { }
15     node(int d) : data(d), left(NULL), right(NULL) { }
16 };
17 
18 int LISS(node *root) {
19     if (!root) return 0;
20     int sum = 1;
21     if (root->left) sum += LISS(root->left->left) + LISS(root->left->right);
22     if (root->right) sum += LISS(root->right->left) + LISS(root->right->right);
23     return max(sum, LISS(root->left) + LISS(root->right));
24 }
25 
26 int main() {
27     node *root = new node(20);
28     root->left = new node(8);
29     root->right = new node(22);
30     root->left->left = new node(4);
31     root->left->right = new node(12);
32     root->left->right->left = new node(10);
33     root->left->right->right = new node(14);
34     root->right->right = new node(25);
35     cout << LISS(root);
36     return 0;
37 }