https://practice.geeksforgeeks.org/problems/implement-queue-using-linked-list/1#
Implement a Queue using Linked List. A Query Q is of 2 Types (i) 1 x (a query of this type means pushing 'x' into the queue) (ii) 2 (a query of this type means to pop an element from the queue and print the poped element)
Example 1:
Input: Q = 5 Queries = 1 2 1 3 2 1 4 2 Output: 2 3 Explanation: n the first testcase 1 2 the queue will be {2} 1 3 the queue will be {2 3} 2 poped element will be 2 the queue will be {3} 1 4 the queue will be {3 4} 2 poped element will be 3.
Example 2:
Input: Q = 4 Queries = 1 2 2 2 1 3 Output: 2 -1 Explanation: In the second testcase 1 2 the queue will be {2} 2 poped element will be {2} then the queue will be empty. 2 the queue is empty and hence -1 1 3 the queue will be {3}. Your Task: Complete the function push() which takes an integer as input parameter and pop() which will remove and return an element(-1 if queue is empty).
Expected Time Complexity: O(1). Expected Auxiliary Space: O(1).
Constraints: 1 <= Q <= 100 1 <= x <= 100