Priority Queue Introduction and Concept in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a priority queue node structure with an integer priority.

DSA C

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

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

Apriority

Bvalue

Cindex

Dweight

Attempts:

3 left

💡 Hint

Common Mistakes

Using a generic name like 'value' instead of 'priority'.

Confusing priority with data.

The field 'priority' stores the priority value for each node in the priority queue.

2fill in blank

medium

Complete the code to insert a new node into the priority queue based on priority order (higher priority first).

DSA C

void insert(Node** head, int data, int priority) {
    Node* newNode = malloc(sizeof(Node));
    newNode->data = data;
    newNode->priority = priority;
    newNode->next = NULL;

    if (*head == NULL || (*head)->priority < [1]) {
        newNode->next = *head;
        *head = newNode;
    } else {
        Node* temp = *head;
        while (temp->next != NULL && temp->next->priority >= priority) {
            temp = temp->next;
        }
        newNode->next = temp->next;
        temp->next = newNode;
    }
}

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AnewNode->priority

Bdata

CnewNode->data

Dpriority

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with 'data' instead of 'priority'.

Using 'priority' instead of 'newNode->priority' in the condition.

We compare the priority of the new node with the head node's priority to decide insertion at the front.

3fill in blank

hard

Fix the error in the dequeue function that removes the highest priority node from the queue.

DSA C

int dequeue(Node** head) {
    if (*head == NULL) {
        return -1; // Queue empty
    }
    Node* temp = *head;
    int data = temp->data;
    *head = [1];
    free(temp);
    return data;
}

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A*head->next

Btemp->next

Chead->next

D(*head)->next

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'head->next' which is invalid because head is a double pointer.

Using '*head->next' which is parsed incorrectly.

To remove the head node, we set *head to the next node using (*head)->next.

4fill in blank

hard

Fill both blanks to complete the function that prints the priority queue nodes in order.

DSA C

void printQueue(Node* head) {
    Node* current = head;
    while (current != NULL) {
        printf("Data: %d, Priority: %d\n", current->[1], current->[2]);
        current = current->next;
    }
}

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Adata

Bnext

Cpriority

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'next' or 'value' instead of 'data' or 'priority'.

Mixing up the order of fields.

We print the 'data' and 'priority' fields of each node.

5fill in blank

hard

Fill all three blanks to complete the function that checks if the priority queue is empty.

DSA C

int isEmpty(Node* [1]) {
    return [2] == [3];
}

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Ahead

CNULL

Dtemp

Attempts:

3 left

💡 Hint

Common Mistakes

Using an undefined variable like 'temp'.

Comparing to 0 instead of NULL.

We check if the pointer 'head' is equal to NULL to determine if the queue is empty.