Insert at Beginning of Doubly Linked List in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new node with given data.

DSA C

struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
newNode->data = [1];
newNode->prev = NULL;
newNode->next = NULL;

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ANULL

Bdata

Chead

DnewNode

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning NULL instead of data to newNode->data.

Using head instead of data for newNode->data.

The new node's data field should be set to the given data value.

2fill in blank

medium

Complete the code to link the new node's next pointer to the current head.

DSA C

newNode->next = [1];

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ANULL

BnewNode->prev

Chead

DnewNode

Attempts:

3 left

💡 Hint

Common Mistakes

Setting newNode->next to NULL instead of head.

Setting newNode->next to newNode itself.

The new node's next pointer should point to the current head node.

3fill in blank

hard

Fix the error in updating the previous pointer of the old head node.

DSA C

if (head != NULL) {
    head->[1] = newNode;
}

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Adata

Bnext

Chead

Dprev

Attempts:

3 left

💡 Hint

Common Mistakes

Updating the next pointer instead of prev.

Trying to assign to head instead of head->prev.

The old head's previous pointer should point back to the new node.

4fill in blank

hard

Fill both blanks to update the head pointer and complete the insertion.

DSA C

head = [1];
return [2];

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AnewNode

Bhead

CNULL

DnewNode->next

Attempts:

3 left

💡 Hint

Common Mistakes

Returning NULL instead of the updated head.

Assigning head to newNode->next instead of newNode.

The head pointer should be updated to the new node, and the updated head returned.

5fill in blank

hard

Fill all three blanks to complete the insertAtBeginning function.

DSA C

struct Node* insertAtBeginning(struct Node* head, int data) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = [1];
    newNode->prev = NULL;
    newNode->next = [2];
    if (head != NULL) {
        head->prev = [3];
    }
    head = newNode;
    return head;
}

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

Adata

Bhead

CnewNode

DNULL

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up pointers for next and prev.

Not updating head->prev when head is not NULL.

Assign data to newNode->data, link newNode->next to head, and update head->prev to newNode.