For the last problem our suggested solutions had O(N) time and/or O(N) space complexity.
We can’t improve the time complexity. We have to visit each value to determine whether or not it is a duplicate.
We can reduce the space complexity to O(1) with an in-place solution.
We’ll adjust the problem to allow for this space complexity. Now we want to alter a sorted input list with all duplicates moved to the end of the list.
The return value will be the index of the final unique value.
duplicates = ['a', 'a', 'g', 't', 't', 'x', 'x', 'x']
remove_dups(duplicates)
# 3, index of the last unique value: 'x'
duplicates
# ['a', 'g', 't', 'x' 'a', 'x', 't', 'x']Clarifying Questions:
Write a function move_duplicates() which has one parameter: dupe_list.
The argument to move_duplicates() will always be a sorted list which may have duplicated values.
move_duplicates() should move all duplicate values to the end of the list and maintain sorted order.
The return value is the index of the last unique value.