Algorithm

We will use two pointers: one at the start of the string (left) and another just next to it (right).
Move the right pointer until we encounter a space or the end of the string, indicating the end of a word.
Whenever a space is found, we have a complete word and we will check the frequency of each letter in the word between the left and right pointers.
To track the letter frequencies, we will use a frequency array (hashing each letter).
If any letter appears more than once, this word becomes a candidate for the answer.
Repeat this process for each word in the string.
At the end, we will print the word with the highest number of repeated letters.