http://www.geeksforgeeks.org/inorder-tree-traversal-without-recursion-and-without-stack/
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 void print(node * root) { 18 if (!root) return ; 19 node *cur = root; 20 while (cur) { 21 if (!cur-> left) { 22 cout << cur->data << " " ; 23 cur = cur-> right; 24 } 25 else { 26 node *pre = cur-> left; 27 while (pre->right && pre->right != cur) pre = pre-> right; 28 if (pre->right == NULL) { 29 pre->right = cur; 30 cur = cur-> left; 31 } 32 else { 33 pre->right = NULL; 34 cout << cur->data << " " ; 35 cur = cur-> right; 36 } 37 } 38 } 39 } 40 41 void prints(node * root) { 42 if (!root) return ; 43 prints(root-> left); 44 cout << root->data << " " ; 45 prints(root-> right); 46 } 47 48 int main() { 49 node* root = new node( 1 ); 50 root->left = new node( 2 ); 51 root->right = new node( 3 ); 52 root->left->left = new node( 4 ); 53 root->left->right = new node( 5 ); 54 print(root); 55 return 0 ; 56 }
Data Structure Binary Tree: Inorder Tree Traversal without recursion and without stack!