void input_deque()
{ int option,val;
clrscr();
do{ printf("\n ********** input deque menu ********");
printf("\n 1.insert at right");
printf("\n 2. delete from left");
printf("\n 3. delete from right");
printf("\n 4. display");
printf("\n enter your choice");
scanf("%d",&option);
switch(option)
{ case 1: printf("\n enter value to be inserted");
scanf("%d",&val);
insert_r(val);
break;
case 2: val=delete_f();
if(val!=-999)
printf("\n value deleted from left is = %d",val);
break;
case 3: val=delete_r();
if(val!=-999)
printf("\n value deleted from right is = %d",val);
break;
case 4: display();
break;
default: printf("\n wroung statement");
}
}while(option<=4 && option>=1);
}
spltreeNode_t* cdsl_spltreeDelete(spltreeRoot_t* root, trkey_t key) {
if (!root)
return NULL;
uint8_t context = ROOT;
spltreeNode_t* delNode = NULL;
root->entry = delete_r(root->entry, key, &context, &delNode);
return delNode;
}
static spltreeNode_t* delete_r(spltreeNode_t* current, trkey_t key, uint8_t* context, spltreeNode_t** found) {
if (!current) {
*context = NOT_FOUND;
*found = NULL;
return NULL;
}
if (current->key == key) {
*found = current;
if (current->left) {
current = largest_r(current->left, context, FALSE, TRUE);
*context = FOUND;
if (current == (*found)->left) {
current->right = (*found)->right;
return current;
}
} else if (current->right) {
current = smallest_r(current->right, context, FALSE, TRUE);
*context = FOUND;
if (current == (*found)->right) {
current->left = (*found)->left;
return current;
}
} else {
*context = FOUND;
return NULL;
}
current->left = (*found)->left;
current->right = (*found)->right;
return current;
}
uint8_t direction = *context;
if (current->key < key) {
*context = RIGHT;
current->right = delete_r(current->right, key, context, found);
if (!current->right){
return current;
}
switch (*context) {
case NOT_FOUND:
return current;
case ZIGZIG_STEP:
*context = FOUND;
return rotateLeft(rotateLeft(current));
case ZIGZAG_STEP:
*context = FOUND;
current->right = rotateRight(current->right);
return rotateLeft(current);
}
if (direction == ROOT) {
return rotateLeft(current);
}
if (*context == FOUND) {
*context = (direction == RIGHT ? ZIGZIG_STEP : ZIGZAG_STEP);
return current;
}
} else {
*context = LEFT;
current->left = delete_r(current->left, key, context, found);
if (!current->left) {
return current;
}
switch (*context) {
case NOT_FOUND:
return current;
case ZIGZIG_STEP:
*context = FOUND;
return rotateRight(rotateRight(current));
case ZIGZAG_STEP:
*context = FOUND;
current->left = rotateLeft(current->left);
return rotateRight(current);
}
if (direction == ROOT)
return rotateRight(current);
if (*context == FOUND) {
*context = (direction == LEFT ? ZIGZIG_STEP : ZIGZAG_STEP);
return current;
}
}
return NULL;
}