Collision Handling Using Chaining in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the head of the linked list to NULL in the hash table.

DSA C

hashTable->buckets[index].head = [1];

Drag options to blanks, or click blank then click option'

ANULL

Bhead

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 instead of NULL which is less clear.

Assigning 1 or an uninitialized variable.

In chaining, each bucket's linked list head should start as NULL to indicate it is empty.

2fill in blank

medium

Complete the code to create a new node and assign the key value in the chaining linked list.

DSA C

newNode = (Node*)malloc(sizeof(Node));
newNode->key = [1];

Drag options to blanks, or click blank then click option'

ANULL

Bkey

Cindex

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning value or index instead of key.

Assigning NULL which is invalid for key.

The new node's key field should be assigned the key passed to the insert function.

3fill in blank

hard

Fix the error in the code to insert the new node at the beginning of the linked list for chaining.

DSA C

newNode->next = [1];
hashTable->buckets[index].head = newNode;

Drag options to blanks, or click blank then click option'

AhashTable->buckets[index].head

BnewNode

CNULL

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Setting next to newNode causes a cycle.

Setting next to NULL loses the existing list.

The new node's next pointer should point to the current head of the list before updating the head.

4fill in blank

hard

Fill both blanks to complete the search function that traverses the linked list to find a key.

DSA C

Node* current = hashTable->buckets[index].head;
while (current != [1]) {
    if (current->key == [2]) {
        return current;
    }
    current = current->next;
}

Drag options to blanks, or click blank then click option'

ANULL

Bkey

C0

Dindex

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 instead of NULL to check end of list.

Comparing with index instead of key.

The loop continues until current is NULL, and compares current->key with the search key.

5fill in blank

hard

Fill all three blanks to complete the delete function that removes a node with a given key from the chain.

DSA C

Node* current = hashTable->buckets[index].head;
Node* prev = [1];
while (current != NULL && current->key != [2]) {
    prev = current;
    current = current->next;
}
if (current == NULL) return;
if (prev == NULL) {
    hashTable->buckets[index].head = current->next;
} else {
    prev->next = [3];
}
free(current);

Drag options to blanks, or click blank then click option'

ANULL

Bkey

Ccurrent->next

DhashTable->buckets[index].head

Attempts:

3 left

💡 Hint

Common Mistakes

Initializing prev to head instead of NULL.

Comparing with index instead of key.

Setting prev->next to current instead of current->next.

Initially, prev is NULL. We look for the node with the key. If prev is NULL, we update head. Otherwise, prev->next skips the deleted node.