What are collections in Java?

Implement a HashMap collection in Java.

Find the maximum continuous subarray sum of an unsorted array, consisting both positive and negative elements / Kadane’s algorithm. (Written Code)

Puzzle: There is a worker, working for 7 days. You have a long piece of gold, of which you give 1/7th of the piece to the worker daily. Find the minimum number of cuts required to make in the gold piece, such that the worker gets his fair share each day.

There is a bank, containing ‘c’ counters. There are ‘n’ people standing in a queue. The counters open at 9:00 A.M. There is also an array a[n] given, containing the time taken by every person to coomplete his/her query at the counter. Whenever one counter gets empty, the very next person in the queue goes to that particular empty counter. Find at what time the x’th person (x <= n) will have his/her turn and at which counter. A fully working code was expected, considering all the base cases and exceptions, with proper syntax. (Written Code)

Given a linked list, check whether the linked list contains a loop. (Written Code)