Question 1 - Decode String

Given an encoded string, return its decoded string.

The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times. Note that k is guaranteed to be a positive integer.

You may assume that the input string is always valid; there are no extra white spaces, square brackets are well-formed, etc. Furthermore, you may assume that the original data does not contain any digits and that digits are only for those repeat numbers, k. For example, there will not be input like 3a or 2[4].

The test cases are generated so that the length of the output will never exceed 10⁵.

Example 1:

Input: s = "3[a]2[bc]"
Output: "aaabcbc"

Example 2:

Input: s = "3[a2[c]]"
Output: "accaccacc"

Example 3:

Input: s = "2[abc]3[cd]ef"
Output: "abcabccdcdcdef"

Constraints:

1 <= s.length <= 30
s consists of lowercase English letters, digits, and square brackets '[]'.
s is guaranteed to be a valid input.
All the integers in s are in the range [1, 300].

Question 2 - Maximum Subarray

Given an integer array nums, find the subarray with the largest sum, and return its sum.

Example 1:

Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
Output: 6
Explanation: The subarray [4,-1,2,1] has the largest sum 6.

Example 2:

Input: nums = [1]
Output: 1
Explanation: The subarray [1] has the largest sum 1.

Example 3:

Input: nums = [5,4,-1,7,8]
Output: 23
Explanation: The subarray [5,4,-1,7,8] has the largest sum 23.

Constraints:

1 <= nums.length <= 10⁵
-10⁴ <= nums[i] <= 10⁴

Follow up: If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.

Question 3

Alice and her friends appeared in CISCO hackathon and they are very exicted . In hackathon htey have given a programming question on string in which Alice and her team needs to form a string of length n by using two characters 'A' and 'B' in which two consecutive B's are not allowed .
Alice can generate any string by using permutation and satisfying the above condition . So, Alice and her team can make any number of strings but there is one more condition in which they need to sort all the the possible strings in lexographical order and they provide a string as output which comes at a particular index mentioned in question.

Input Format :

T - Test Cases
N - number of characters M - index
1<=t<=10
1<=N<=100
1<=M<=10⁹

Input -
2
2 3
2 4


Output -
BA
Not possible

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