Software Engineer Intern

Given a string ‘STR’ consisting of lower case English letters, the task is to find the first non-repeating character in the string and return it. If it doesn’t exist, return ‘#’.

For example:

For the input string 'abcab', the first non-repeating character is ‘c’. As depicted the character ‘a’ repeats at index 3 and character ‘b’ repeats at index 4. Hence we return the character ‘c’ present at index 2.

You are given an array “A” of N integers. Your task is to find the maximum element in all K sized contiguous subarrays from left to right.

For Example:

If A = [3, 2, 3], and K = 2.
Then max of [3, 2] = 3 and max of [2, 3] = 3
So, the answer will be [3, 3]

If A = [3, 2, 3, 5, 1, 7] and K = 3.
Then max of [3, 2, 3] = 3 
Then max of [2, 3, 5] = 5 
Then max of [3, 5, 1] = 5 
Then max of [5, 1, 7] = 7 
So  the answer will be [3, 5, 5, 7]

Follow Up :

Can you solve the problem in O(N) time complexity and O(K) space complexity?

The lowest common ancestor (LCA) is a concept in graph theory and computer science.

Let ‘T’ be a rooted tree with ‘N’ nodes. The lowest common ancestor is defined between two nodes, ‘u’ and ‘v’, as the lowest node in ‘T’ that has both ‘u’ and ‘v’ as descendants (where we allow a node to be a descendant of itself). - Wikipedia

For the given tree, The LCA of nodes 5 and 8 will be node 2, as node 2 is the first node that lies in the path from node 5 to root node 1 and from node 8 to root node 1.

Path from node 5 to root node looks like 5 → 2 → 1.

Path from node 8 to root node looks like 8 → 6 → 2 → 1.

Since 2 is the first node that lies in both paths. Hence LCA will be 2.

Given any two nodes ‘u’ and ‘v’, find the LCA for the two nodes in the given Tree ‘T’.

Note: For each test case, the tree is rooted at node 1.

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