Senior Software Engineer

You are given an array of integers 'ARR' containing N elements. Each integer is in the range [1, N-1], with exactly one element repeated in the array.

Your task is to find the duplicate element. The duplicate element may be repeated more than twice in the error, but there will be exactly one element that is repeated in the array.

Note :

All the integers in the array appear only once except for precisely one integer which appears two or more times.

1. Need to write the code to run multiple threads and use synchronised block/method on Notepad.
2. Design Patterns, Joins on multi-threading, Streams

You are given a string 'STR' containing lowercase English letters from a to z inclusive. Your task is to find all non-empty possible subsequences of 'STR'.

A Subsequence of a string is the one which is generated by deleting 0 or more letters from the string and keeping the rest of the letters in the same order.

Need to design a custom Cache System like Redis.

Given valid mathematical expressions in the form of a string. You are supposed to return true if the given expression contains a pair of redundant brackets, else return false. The given string only contains ‘(‘, ’)’, ‘+’, ‘-’, ‘*’, ‘/’ and lowercase English letters.

Note :

A pair of brackets is said to be redundant when a subexpression is surrounded by needless/ useless brackets.

For Example :

((a+b)) has a pair of redundant brackets. The pair of brackets on the first and last index is needless. 
While (a + (b*c)) does not have any pair of redundant brackets. 

Basic Introduction, Current role and package. Expectations.