Doubly Linked List Structure and Node Design in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a node structure for a doubly linked list.

DSA C

typedef struct Node {
    int data;
    struct Node* prev;
    struct Node* [1];
} Node;

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

Anext

Bprevious

Clink

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'previous' instead of 'next' for the forward pointer.

Using unrelated names like 'child' or 'link'.

The 'next' pointer points to the next node in the doubly linked list, allowing traversal forward.

2fill in blank

medium

Complete the code to create a new node dynamically.

DSA C

Node* createNode(int value) {
    Node* newNode = (Node*)malloc(sizeof([1]));
    if (newNode == NULL) return NULL;
    newNode->data = value;
    newNode->prev = NULL;
    newNode->next = NULL;
    return newNode;
}

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ANode*

Bnode

Cstruct Node

DNode

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'node' which is undefined.

Using 'struct Node' when typedef is used.

Using pointer type 'Node*' inside sizeof.

We allocate memory for the 'Node' structure type to create a new node.

3fill in blank

hard

Fix the error in the function to initialize a doubly linked list node.

DSA C

void initNode(Node* node, int val) {
    node->data = val;
    node->prev = NULL;
    node->[1] = NULL;
}

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

Anext

Bprevious

Clink

Dchild

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'previous' which is not declared.

Using unrelated pointer names.

The pointer to the next node must be set to NULL to mark the end of the list.

4fill in blank

hard

Fill both blanks to correctly link two nodes in a doubly linked list.

DSA C

void linkNodes(Node* first, Node* second) {
    first->[1] = second;
    second->[2] = first;
}

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Anext

Bprev

Cprevious

Dlink

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up 'next' and 'prev' pointers.

Using undefined pointer names like 'previous' or 'link'.

The first node's 'next' points to the second node, and the second node's 'prev' points back to the first node.

5fill in blank

hard

Fill all four blanks to insert a new node between two existing nodes.

DSA C

void insertBetween(Node* prevNode, Node* newNode, Node* nextNode) {
    newNode->[1] = nextNode;
    newNode->[2] = prevNode;
    prevNode->[3] = newNode;
    nextNode->[4] = newNode;
}

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Anext

Bprev

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to update prevNode's next pointer.

Forgetting to update nextNode's prev pointer.

Mixing up 'next' and 'prev' pointers.

The new node's 'next' points to the next node, its 'prev' points to the previous node, the previous node's 'next' points to the new node, and the next node's 'prev' points to the new node.