/* Approach
* generate list for left tree call it as l1
* generate list for right tree call it as l2
* sandwitch node between l1 and l2 = l1 + node + l2
* keep doing it recursively.
*/
void bst2dll(Node *node, Node **head, Node **tail) {
Node *h1,*t1,*h2,*t2;
// If this is the NULL node , then do not return any list
if (node == NULL) {
if (head) *head = NULL;
if (tail) *tail = NULL;
return;
}
// recursively generate list for left and right tree
bst2dll(node->left, &h1, &t1);
bst2dll(node->right, &h2, &t2);
// add the node between two lists.
node->left = t1; if(t1) t1->right = node;
node->right = h2; if(h2) h2->left = node;
// If right and left tree are empty then
// return tree with one element only
// else return head or left list as new head
// and tail of right list as new tail.
if (head) *head = h1? h1 : node;
if (tail) *tail = t2? t2 : node;
}
struct BSTNode* bst2dll(struct BSTNode* root, struct BSTNode* prev){
if(root==NULL)
return prev;
prev = bst2dll(root->left,prev);
root->left = prev;
if(prev)
prev->right = root;
prev = root;
prev = bst2dll(root->right,prev);
return prev;
}
/* binary search tree to double linked list */
void bst2dll(BSTreeNode * root, BSTreeNode ** prev)
{
if (root == NULL)
return;
bst2dll(root->left, prev);
if (*prev)
(*prev)->right = root;
root->left = *prev;
*prev = root;
bst2dll(root->right, prev);
}
int main(int argc, char **argv)
{
Node *root = NULL;
Node *dl, *tl;
int v;
for(int i = 0; i < 10; i++) {
v = rand() % 100;
printf("%d ", v);
insert_bst(&root, v);
}
printf("\n");
print_bst(root);
printf("\n");
bst2dll(root, &dl, &tl);
printf("%p %p\n", dl, tl);
print_list(dl);
return 0;
};
int main(){
printf("Creating a binary search tree\n");
struct BSTNode* root =NULL;
root = createBST(root);
struct BSTNode* prev = NULL;
struct BSTNode* temp=bst2dll(root,prev);
struct BSTNode* temp1;
while(temp!= NULL){
printf("%d\n",temp->value);
temp1 = temp;
temp = temp->left;
}
while(temp1!=NULL){
printf("%d\n",temp1->value);
temp1 = temp1->right;
}
return 0;
}
int
main(int argc, char** argv) {
random_bst();
struct node* bst_root = generate_bst(20);
printf("Pre-order\n");
pre_order_bst(bst_root);
printf("\n");
printf("level-order\n");
level_order_bst(bst_root);
printf("\n");
printf("Is a bst? %d\n", is_bst(bst_root));
in_order_bst(bst_root);
printf("\n");
struct dll list;
bst2dll(bst_root, &list);
print_dll(list);
destruct_dll(list);
return 0;
}
int main()
{
BSTreeNode * nodes = (BSTreeNode*)malloc(sizeof(BSTreeNode)*7);
nodes[0].value = 10;
nodes[0].left = &nodes[1];
nodes[0].right = &nodes[2];
nodes[1].value = 6;
nodes[1].left = &nodes[3];
nodes[1].right = &nodes[4];
nodes[3].value = 4;
nodes[3].left = NULL;
nodes[3].right = NULL;
nodes[4].value = 8;
nodes[4].left = NULL;
nodes[4].right = NULL;
nodes[2].value = 14;
nodes[2].left = &nodes[5];
nodes[2].right = &nodes[6];
nodes[5].value = 12;
nodes[5].left = NULL;
nodes[5].right = NULL;
nodes[6].value = 16;
nodes[6].left = NULL;
nodes[6].right = NULL;
BSTreeNode * prev = NULL;
bst2dll(&nodes[0], &prev);
while (prev) {
printf("%d ", prev->value);
prev = prev->left;
}
free(nodes);
return 0;
}
