Question 1:

Given a string, you have to return the first word in the string having the most number of repeating characters.

Example:

"Today is the greatest day ever!"

Answer:

"greatest."

Both "greatest" and "ever" have the same number of repeating characters, at a maximum of 2 (e's & t's in "greatest" and 2 e's in "ever"). 
However, "greatest" occurs first, so "greatest" will be the answer.

Approach:

To obtain each specific word in the string, you can traverse by segmenting words on punctuation. I used stringstream in C++. 
Then, I used a map for each word to track the frequency of characters, then have a global maximum variable and a string called the result word. 
Normal traversal over stringstream and hashing to get the first word in the string having the most number of repeating characters.

Overall Approach: StringStream + hashing.

Time complexity: O(n*m)

Space Complexity: O(m)

Where n is the length of the string, and m is the length of the largest word in the string.

I accomplished all this in 10-15 minutes.

Question 2:

Given an array, return true or false.

Condition:

True -> If there exists a combination that sums to the maximum element in the array without using the maximum element.

False -> Otherwise.

Example: [1,3,4,5,12]

Answer: True.

(3,4,5 -> 12)

This problem is similar to the Target Sum problem on LeetCode with a modification.

Approach:

Get the maximum element in the array and form a new array/vector without the maximum element. After this, apply a recursive approach to 
find the subsequence with the target sum.

Overall Approach: Find the maximum + get the new vector without the maximum + Recursion + dynamic programming (target*n).

Time Complexity: O(n*maximum_element)

Space Complexity: O(n*maximum_element)