This Java module deals with Stacks, Queues, and ArrayLists. We'll perform various operations on them.
Given a stack of integers and Q queries. The task is to perform operation on stack according to the query.
First line of input contains nubmer of testcases T. For each testcase, first line of input contains Q, number of queries. Next line contains Q queries seperated by space. Queries are as:
i x : (adds element x in the stack).
r : (returns and removes the topmost element from the stack).
h : Prints the topmost element.
f y : (check if the element y is present or not in the stack). Print "Yes" if present, else "No".
For each testcase, perform Q queries and print the output wherever required.
Your task is to complete functions insert(), remove(), headOf_Stack() and find(), to insert, remove returning top element and findiing the elment in stack respectively.
1 <= T <= 100
1 <= Q <= 103
i 2 i 4 i 3 i 5 h f 8
i 3 i 4 r f 3
Testcase 1: Inserting 2, 4, 3, and 5 onto the stack. Returning top element which is 5. Finding 8 will give No, as 8 is not in the stack.
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