Final answer:
The variable max_dup should be set to -1 initially and updated to the largest duplicated element in the list if any duplicates are found. A dictionary is used to keep track of the occurrences of elements. The correct option is D) -1, indicating that no duplicates were found if max_dup remains -1.
Step-by-step explanation:
To solve the problem of finding the largest duplicated element in a list of positive integers, we can follow a systematic approach. The first step would be to initialize a variable, max_dup, to -1, which will hold our result. This is because we start with the assumption that there are no duplicates, and if we find any duplicates, we will update this variable accordingly.
Next, we must iterate through the list and keep track of the occurrences of each element. A dictionary can serve as a good data structure to maintain the count of each element. As we iterate through the list, we will update the count for each element in the dictionary. If the current element's count reaches 2 (meaning it's a duplicate), we will then compare it with max_dup. If the current element is larger, we'll update max_dup with the current element's value.
After we've finished iterating through the list, max_dup will contain the value of the largest duplicated element if there were duplicates in the list. If max_dup is still -1 at the end of the iteration, this implies there were no duplicates in the list. In that case, max_dup will retain the value -1, indicating no duplicates were found.
The correct option for the question is D) -1, as it is the value associated with max_dup when no duplicates are present in the list.