GATE 2025 Programming & Data Structures Foundation Quiz 4

If the elements “A”, “B”, “C” and “D” are placed in a queue and are deleted one at a time, in what order will they be removed?

Consider the following statements about double-ended queue :
S1 : Enqueue and Dequeue can take place from both ends.
S2 : Doesn’t follow FIFO policy.
S3 : Alternatively enqueue and dequeue is performed from two different ends.
Which of the above statements are correct?

Convert the following prefix expression into a postfix expression :

* – + A B C D

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 REAR and FRONT as array index variables, respectively. Initially, REAR = FRONT = 0. Which of the following conditions to detect queue full and empty queue?