retry.py

#! Python
# github.com/stevieoj

# 1. Given an array of N integers, find maximum difference, where the index of the largest number is greater than 
# the index of smallest number. If not find the next smallest number. If condition cannot be met return -1.

# Time complexity: O(n)
# Space Complexity: O(1)

def max_difference(xs):
    min_elem = xs[0]
    max_elem = xs[0]
    max_diff = -1

    for elem in xs[1:]:
        min_elem = min(elem, min_elem)
        if elem > max_elem:
            max_diff = max(max_diff, elem - min_elem)
            max_elem = elem

    return max_diff



# 2. James found a love letter his friend Harry has written for his girlfriend. James is a prankster, so he decides to 
# meddle with the letter. He changes all the words in the letter into palindromes.

# To do this, he follows two rules:
# He can reduce the value of a letter, e.g. he can change d to c, but he cannot change c to d.
# In order to form a palindrome, if he has to repeatedly reduce the value of a letter, he can do it until the letter becomes a. 
# Once a letter has been changed to a, it can no longer be changed.
# Each reduction in the value of any letter is counted as a single operation. Find the minimum number of operations required to 
# convert a given string into a palindrome.
# Time complexity: O(n/2)
# Space complexity: O(1)

    def  theLoveLetterMystery(s):
    out = 0
    for i in range(len(s) // 2):
       # ord method -> finds unicode point
        out += abs(ord(s[i]) - ord(s[len(s) - i - 1]))
    return out