Reverse a Singly Linked List Recursive in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the list is empty or has one node.

DSA C

if (head == NULL || head->[1] == NULL) {
    return head;
}

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Avalue

Bprev

Cdata

Dnext

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' instead of 'next' in a singly linked list.

Checking the data value instead of the next pointer.

The base case for recursion checks if the list is empty or has only one node by checking if head or head->next is NULL.

2fill in blank

medium

Complete the code to recursively reverse the rest of the list.

DSA C

struct Node* rest = [1](head->next);

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AprintList

BfreeList

CreverseList

DdeleteList

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function that frees or deletes the list instead of reversing.

Calling a print function instead of recursive reverse.

The function calls itself recursively to reverse the rest of the list starting from head->next.

3fill in blank

hard

Fix the error in setting the next node's next pointer to the current head.

DSA C

head->next->[1] = head;

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Aprev

Bnext

Cdata

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' which does not exist in singly linked list nodes.

Trying to assign to data or value fields.

To reverse the link, set head->next->next to head, changing the direction of the pointer.

4fill in blank

hard

Fill both blanks to complete the recursive reversal and break the old link.

DSA C

head->[1] = NULL;
return [2];

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Anext

Brest

Cprev

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Returning head instead of rest.

Not setting head->next to NULL causing cycles.

After reversing, set head->next to NULL to break the old link and return the new head stored in rest.

5fill in blank

hard

Fill all three blanks to complete the full recursive reverse function.

DSA C

struct Node* reverseList(struct Node* head) {
    if (head == NULL || head->[1] == NULL) {
        return head;
    }
    struct Node* [2] = reverseList(head->next);
    head->next->[3] = head;
    head->next = NULL;
    return [2];
}

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

Anext

Brest

Dprev

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' which is not part of singly linked list node.

Not breaking the old link by setting head->next to NULL.

The function checks if head or head->next is NULL, recursively reverses the rest, sets head->next->next to head, breaks old link, and returns new head.