Intersection Point of Two Linked Lists in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to move the pointer to the next node in the linked list.

DSA C

current = current[1];

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Anext

B->next

C->prev

D.next

Attempts:

3 left

💡 Hint

Common Mistakes

Using dot operator instead of arrow operator for pointer access.

Using 'next' without any operator.

In C, to access the next node pointer from a pointer to a struct, use the arrow operator '->' followed by 'next'.

2fill in blank

medium

Complete the code to check if two pointers point to the same node.

DSA C

if (ptrA [1] ptrB) {
    // Intersection found
}

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A==

B!=

C=

D&&

Attempts:

3 left

💡 Hint

Common Mistakes

Using assignment operator '=' instead of comparison '=='.

Using '!=' which checks for inequality.

To check if two pointers point to the same node, use the equality operator '=='.

3fill in blank

hard

Fix the error in the loop condition to traverse the linked list until the pointer is NULL.

DSA C

while (current [1] NULL) {
    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 the loop to run only when current is NULL, which is incorrect.

Using '<' or '>' operators with pointers is invalid.

To traverse until the pointer is NULL, the loop should continue while current is not equal to NULL, using '!='.

4fill in blank

hard

Fill both blanks to correctly advance pointers and handle switching lists when reaching the end.

DSA C

if (ptrA == NULL) {
    ptrA = [1];
} else {
    ptrA = ptrA[2];
}

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AheadB

BheadA

C->next

D->prev

Attempts:

3 left

💡 Hint

Common Mistakes

Switching to the wrong list head.

Using incorrect pointer member like '->prev'.

When ptrA reaches NULL, it should switch to headB. Otherwise, it moves to the next node using '->next'.

5fill in blank

hard

Fill all three blanks to complete the function that finds the intersection point of two linked lists.

DSA C

struct ListNode *getIntersectionNode(struct ListNode *headA, struct ListNode *headB) {
    struct ListNode *ptrA = headA;
    struct ListNode *ptrB = headB;
    while (ptrA != ptrB) {
        ptrA = (ptrA == NULL) ? [1] : ptrA[2];
        ptrB = (ptrB == NULL) ? [3] : ptrB->next;
    }
    return ptrA;
}

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

AheadB

BheadA

C->next

D->prev

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up headA and headB when switching pointers.

Using incorrect pointer member like '->prev'.

When ptrA is NULL, switch to headB; otherwise move to next node with '->next'. For ptrB, switch to headA if NULL, else move to next node.