Data Structure Binary Tree: Morris traversal for Preorder

http://www.geeksforgeeks.org/morris-traversal-for-preorder/

 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 void prints(node *root) {

19     while (root) {

20         if (root->left == NULL) {

21             cout << root->data << " ";

22             root = root->right;

23         }

24         else {

25             node* cur = root->left;

26             while (cur->right && cur->right != root) cur = cur->right;

27             if (cur->right == NULL) {

28                 cout << root->data << " ";

29                 cur->right = root;

30                 root = root->left;

31             }

32             else {

33                 cur->right = NULL;

34                 root = root->right;

35             }

36         }

37     }

38 }

39 

40 int main() {

41     node *root = new node(1);

42     root->left = new node(2);

43     root->right = new node(3);

44     root->left->left = new node(4);

45     root->left->right = new node(5);

46     root->right->left = new node(6);

47     root->right->right = new node(7);

48     root->left->left->left = new node(8);

49     root->left->left->right = new node(9);

50     root->left->right->left = new node(10);

51     root->left->right->right = new node(11);

52     prints(root);

53     return 0;

54 }