SDE - 1

Ninja is sitting in an examination hall. He is encountered with a problem statement, "Find ‘X’ to the power ‘N’ (i.e. ‘X’ ^ ‘N’). Where ‘X’ and ‘N’ are two integers."

Ninja was not prepared for this question at all, as this question was unexpected in the exam.

He is asking for your help to solve this problem. Help Ninja to find the answer to the problem.

Note :

For this question, you can assume that 0 raised to the power of 0 is 1.

Gary has N coins placed in a straight line. Some coins have head side up, and others have the tail side up.

Convention:

1 denotes the HEAD side is up. 
0 denotes the TAIL side is up. 

Now, Gary wants to obtain a maximum number of head-side up coins. He can perform at most one(possibly 0) flip in which he can flip the coins of a continuous interval (continuous subarray).

For example: In the given array (0 based indexing), { 1, 0, 0, 1, 0, 0, 1 }, we can obtain maximum head side up coins by flipping the coins in range 1 to 5. The array will thus become {1, 1, 1, 0, 1, 1, 1 }.

Return the maximum number of heads side up Gary can obtain.

You are given an arbitrary binary tree consisting of N nodes numbered from 1 to N, an integer 'K', and a node 'TARGET_NODE_VAL' from the tree. You need to find the Kth ancestor of the node 'TARGET_NODE_VAL'. If there is no such ancestor, then print -1.

The Kth ancestor of a node in a binary tree is the Kth node in the path going up from the given node to the root of the tree. Refer to sample test cases for further explanation.

Note:

1. The given node 'TARGET_NODE_VAL' is always present in the tree.
2. The value of each node in the tree is unique.
3. Notice that the Kth ancestor node if present will always be unique.

You're given a string 'S' consisting of "{", "}", "(", ")", "[" and "]" .

Return true if the given string 'S' is balanced, else return false.

For example:

'S' = "{}()".

There is always an opening brace before a closing brace i.e. '{' before '}', '(' before ').
So the 'S' is Balanced.

Given a sequence of numbers ‘ARR’. Your task is to return a sorted sequence of ‘ARR’ in non-descending order with help of the merge sort algorithm.

Example :

Merge Sort Algorithm -

Merge sort is a Divide and Conquer based Algorithm. It divides the input array into two-parts, until the size of the input array is not ‘1’. In the return part, it will merge two sorted arrays a return a whole merged sorted array.

The above illustrates shows how merge sort works.

Note :

It is compulsory to use the ‘Merge Sort’ algorithm.

You have been given an encoded string. Your task is to decode it back to the original string.

- An encoded string will be of the form <count>[encoded_string], where the 'encoded_string' inside the square brackets is being repeated exactly 'count' times. Note that 'count' is guaranteed to be a positive integer and can be greater than 9.
- There are no extra white spaces and square brackets are well-formed.

For example -

Input: 2[a]
“a” is encoded 2 times, hence the decoded string will be "aa".

Input: 3[a2[b]]
“b” is encoded 2 times, which decodes as 3[abb]. Now, "abb" is encoded 3 times, hence decoded string will be "abbabbabb".