1.) Problem solving

Problem one solution

def main():
    # input
    # stores
    alphabets, num = str(input()), input()

    if not alphabets.isalpha():
        raise Exception("Expected only alphabets")
    else:
        alphabets = alphabets.lower()

    if not num.isnumeric():
        raise Exception("Expected an interger")

    num = int(num)

    # Complexity O(n)
    for item in alphabets:
        '''
        The logic involves 2 steps
        *) scale down to 0 - 26,by sub 97
        *) add the number to the alphabet(character)
        *) scale the sum between 0 - 26 by using %
        *) up convert to lowercase by adding 97
        
        it does have sub + add + modules operations which are the most fastest 
        operations in a programming language, the time for this is very negligible. This
        makes us to only consider the complexity part, which i believe is minimum for this particular program.
        
        '''
        print(chr(((((ord(item) - 97) + num) % 26) + 97)), end="")


if __name__ == "__main__":
    main()

'''
QA:
1) algorithm + program is mentioned above + complexity is O(n)
2) I don't really understand the 2nd questions(I had used the ascii method to solve the problem :) ).

'''