Queue Data Structure Questions
This Test will cover basic concepts of Queue data Structure and related algorithm.
Q. Which one of the following is an application of Queue Data Structure?
Q. How many stacks are needed to implement a queue. Consider the situation where no other data structure like arrays, linked list is available to you.
Q. How many queues are needed to implement a stack. Consider the situation where no other data structure like arrays, linked list is available to you.
Q. A Priority Queue can be efficiently implemented using which of the following data structures?
Q. Which of the following is true about linked list implementation of queue?
Q. Suppose a Circular queue of capacity
(n - 1) elements is implemented with an array of
n elements. Assume that the insertion and deletion operation are carried out using
FRONT as array index variables, respectively. Initially,
REAR = FRONT = 0. The conditions to detect, queue is full and queue is empty will be:
Q. A Priority Queue is implemented as a Max-Heap. Initially, it has
5 elements. The level-order traversal of the heap is given below:
10, 8, 5, 3, 2. Two new elements
7 are inserted in the heap in that order. The level-order traversal of the heap after the insertion of the elements will be:
Q. Consider the following operation along with
Dequeue operations on a Queue, where
k is a global parameter. What will be the worst case time complexity of a sequence of
MultiDequeue() operations if the queue is empty initially?
m = k;
while (Q is not empty and m > 0)
m = m - 1;
Q. Suppose a stack implementation supports an operation
REVERSE, which reverses the order of elements on the stack, in addition to the
POP operations. Which one of the following statements is TRUE with respect to this modified stack?
Q. A queue is implemented using an array such that
DEQUEUE operations are performed efficiently. Which one of the following statements is CORRECT if the array is circular. (
n refers to the number of items in the queue)?
Q. Consider the following pseudocode. Assume that
IntQueue is an integer queue. What does the function
void fun(int n)
IntQueue q = new IntQueue();
for (int i = 0; i < n; i++)
int a = q.dequeue();
int b = q.dequeue();
q.enqueue(a + b);
Q. A queue is implemented using a non-circular singly linked list. The queue has a
pointer and a
pointer, as shown in the figure. Let
denote the number of nodes in the queue. Let
be implemented by inserting a new node at the
be implemented by deletion of a node from the
Which one of the following is the time complexity of the most time-efficient implementation of
, respectively, for this data structure?
Q. Suppose you are given an implementation of a queue of integers. The operations that can be performed on the queue are:
isEmpty(Q): returns true if the queue is empty, false otherwise.
delete(Q): deletes the element at the front of the queue and returns its value.
insert(Q, i): inserts the integer i at the rear of the queue.
Consider the following function:
void f(queue Q)
int i ;
i = delete(Q);
What operation is performed by the above function
Q. An implementation of a queue
Q, using two stacks
S2, is given below. If
n insert and
m (<= n) delete operations were performed in an arbitrary order on an empty queue
y be the number of push and pop operations performed respectively in the process. Which one of the following is true for all values of
void insert(Q, x)
push (S1, x);
print("Q is empty");
x = pop(S1);
x = pop(S2);
Q. Following is a C like pseudocode for a function that takes a Queue as an argument, and uses a stack
S to do the processing. What does the function do in general?
void fun(Queue *Q)
Stack S; // Say it creates an empty stack S
// Run while Q is not empty
// deQueue an item from Q and push the dequeued item to S
// Run while Stack S is not empty
// Pop an item from S and enqueue the poppped item to Q
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