Delete Node by Value in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the list is empty before deletion.

DSA C

if (head == [1]) {
    printf("List is empty.\n");
    return head;
}

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

ANULL

B0

Chead

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 instead of NULL for pointer comparison.

Checking if head equals 1 or head itself.

We check if head is NULL to know if the list is empty.

2fill in blank

medium

Complete the code to delete the head node when it matches the value.

DSA C

if (head->data == value) {
    struct Node* temp = head;
    head = head->[1];
    free(temp);
    return head;
}

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

Aprev

Bnext

Cvalue

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using head->prev which does not exist in singly linked list.

Using head->data or head->value which are data fields, not pointers.

To delete the head node, we move head to head->next.

3fill in blank

hard

Fix the error in the loop condition to find the node before the one to delete.

DSA C

while (current->next != NULL && current->next->data [1] value) {
    current = current->next;
}

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

A!=

B==

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' causes loop to stop immediately if first node matches.

Using '>' or '<' is incorrect for equality check.

We continue while current->next->data is not equal to value to find the node before target.

4fill in blank

hard

Fill both blanks to correctly remove the target node from the list.

DSA C

if (current->next != NULL) {
    struct Node* temp = current->[1];
    current->[2] = temp->next;
    free(temp);
}

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

Anext

Bprev

Cdata

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using prev which does not exist in singly linked list.

Using data or value which are data fields, not pointers.

We use current->next to access and remove the target node.

5fill in blank

hard

Fill all three blanks to complete the delete function returning the updated head.

DSA C

struct Node* deleteNode(struct Node* head, int value) {
    struct Node* current = head;
    if (head == [1]) return head;
    if (head->data == value) {
        struct Node* temp = head;
        head = head->[2];
        free(temp);
        return head;
    }
    while (current->next != NULL && current->next->data != value) {
        current = current->next;
    }
    if (current->next != NULL) {
        struct Node* temp = current->next;
        current->next = temp->[3];
        free(temp);
    }
    return head;
}

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

ANULL

Bnext

Dprev

Attempts:

3 left

💡 Hint

Common Mistakes

Using prev pointer which does not exist in singly linked list.

Not updating head when deleting the first node.

Check for empty list with NULL, move head to head->next, and link current->next to temp->next.