#include #include #include typedef struct node1 { int data; int bf; struct node1 *left; struct node1 *right; } node; void insert_node(node **, int); void delete_node(node **, int); int find_height(node *); void delete_tree(node **); node *findmax(node *); void traverse_inorder(node *); int main() { int choice; /* variable to store choice of user */ int element; /* variable to store data of node entered bu user */ node *root = NULL; /* intialising root node */ while (1) { printf("\n\t MENU\n"); printf("\t--------\n"); printf(" 1. Insert node\n"); printf(" 2. Delete node\n"); printf(" 3. Height of Tree\n"); printf(" 4. Traverse inorder\n"); printf(" 5. Exit\n\n"); printf("Enter your choice (1-5) ::"); scanf("%d", &choice); switch (choice) { case 1: printf("\n Enter the element to be inserted::"); scanf("%d", &element); insert_node(&root, element); break; case 2: printf("\n Enter the element to be deleted ::"); scanf("%d", &element); delete_node(&root, element); break; case 3: printf("Height of AVL Tree = %d", find_height(root)); break; case 4: printf("\n\n In-Order Traversal is\n"); traverse_inorder(root); break; case 5: delete_tree(&root); return; } } } void insert_node(node ** root, int element) { node *ptr1; node *ptr2; /* checking if there is no elemnt in th tree */ if(NULL == *root) { *root = (node *) malloc (sizeof(node)); /* allocating memory */ (*root)->data = element; (*root)->left = NULL; (*root)->right = NULL; (*root)->bf = 0; /* allocating balance factor to root */ } /* element is less than root than */ else if(element < (*root)->data) { insert_node(&((*root)->left), element); switch((*root)->bf) { case 1: ptr1 = (*root)->left; if(1 == ptr1->bf) { /* right rotation */ (*root)->left = ptr1->right; ptr1->right = *root; (*root)->bf = 0; *root = ptr1; } else { ptr2 = ptr1->right; ptr1->right = ptr2->left; ptr2->left = ptr1; (*root)->left = ptr2->right; ptr2->right = *root; (*root)->bf = ptr2->bf == 1 ? -1 : 0; ptr1->bf = ptr2->bf == -1 ? 1 : 0; *root = ptr2; } break; case 0: (*root)->bf = 1; break; case -1: (*root)->bf = 0; break; } } else { insert_node(&(*root)->right, element); switch((*root)->bf) { case 1: (*root)->bf = 0; break; case 0: (*root)->bf = -1; break; case -1: ptr1 = (*root)->right; if(ptr1->bf == -1) { /* left rotation */ (*root)->right = ptr1->left; ptr1->left = *root; (*root)->bf = 0; *root = ptr1; } else { /* double rotation ,right left */ ptr2 = ptr1->left; ptr1->left = ptr2->right; ptr2->right = ptr1; (*root)->right = ptr2->left; ptr2->left = (*root); (*root)->bf = ptr2->bf == -1 ? 1 : 0; ptr1->bf = ptr2->bf == 1 ? -1 : 0; *root = ptr2; } } } } int find_height (node *tree) { int height_of_left_subtree; int height_of_right_subtree; int height; if (NULL == tree) { height = 0; } else { height_of_left_subtree = find_height(tree->left); height_of_right_subtree = find_height(tree->right); if(height_of_left_subtree > height_of_right_subtree) height = height_of_left_subtree + 1; else height = height_of_right_subtree + 1; } return height; } void delete_node (node **h, int element) { node *temp; /* variable to store node which has to be freed */ node *ptr1; node *ptr2; if (NULL == *h) { printf("Element %d not found in the AVL tree\n", element); printf("press any key to continue...."); getch(); } else if(element < (*h)->data) { delete_node(&(*h)->left, element); switch((*h)->bf) { case 1: (*h)->bf = 0; break; case 0: (*h)->bf = -1; break; case -1: ptr1 = (*h)->right; if(ptr1->bf == -1) { /* left rotation */ (*h)->right = ptr1->left; ptr1->left = *h; (*h)->bf = 0; *h = ptr1; } else { ptr2 = ptr1->left; ptr1->left = ptr2->right; ptr2->right = ptr1; (*h)->right = ptr2->left; ptr2->left = *h; (*h)->bf = ptr2->bf == -1 ? 1 : 0; ptr1->bf = ptr2->bf == 1 ? -1 : 0; *h = ptr2; } } } else if (element > (*h)->data) { delete_node (&(*h)->right, element); switch ((*h)->bf) { case 1: ptr1 = (*h)->left; if(ptr1->bf == 1) { /* right rotation */ (*h)->left = ptr1->right; ptr1->right = *h; (*h)->bf = 0; *h = ptr1; } else { /* double rotation , left-right */ ptr2 = ptr1->right; ptr1->right = ptr2->left; ptr2->left = ptr1; (*h)->left = ptr2->right; (*h)->bf = ptr2->bf == 1 ? -1 : 0; ptr1->bf = ptr2->bf == -1 ? 1 : 0; *h = ptr2; } break; case 0: (*h)->bf = 1; break; case -1: (*h)->bf = 0; break; } } /* when element found and it has both the child than find predecessor */ else if( (*h)->left && (*h)->right) { temp = findmax((*h)->left); /* find predecessor */ (*h)->data = temp->data; /* replace node with predecessor */ delete_node(&(*h)->left, temp->data); /* delete predecessor */ } else { temp = *h; if(((*h)->left == NULL) && ((*h)->right == NULL)) /* terminal node */ *h = NULL; else if ((*h)->right == NULL) /* left child only */ *h = (*h)->left; else *h = (*h)->right; /* right child only */ free(temp); } } node * findmax(node *root) { if((NULL == root) || (NULL == root->right)) { return root; } else return findmax(root->right); } void traverse_inorder(node *root) { if(NULL != root) { traverse_inorder(root->left); printf("%d, ", root->data); traverse_inorder(root->right); } } void delete_tree(node **root) { if (NULL != *root) { delete_tree(&((*root)->left)); delete_tree(&((*root)->right)); free(root); } }