Implement Adjacent-Line Uniq

Question

Implement a function that removes adjacent duplicate elements from a list, ensuring that only unique elements remain in sequence.

Codemia · Accepted Answer

To solve the problem of removing adjacent duplicates, we can utilize a simple iteration through the list while maintaining a new list to store unique elements. As we traverse the input list, we will compare each element with the last added element in our new list. If they are different, we will append the current element to the new list.

Here is a Python implementation of the approach:

```python
def adjacent_line_uniq(lst):
    if not lst:
        return []
    unique_lst = [lst[0]]  # Start with the first element
    for i in range(1, len(lst)):
        if lst[i] != lst[i - 1]:  # Compare with the previous element
            unique_lst.append(lst[i])
    return unique_lst
```
This function initializes a new list with the first element and iterates through the input list, checking for duplicates.

The time complexity of this solution is O(n), where n is the number of elements in the input list, because we traverse the list once. The space complexity is also O(n) in the worst case, where there are no adjacent duplicates, and we store all elements in the new list.

We should consider edge cases such as an empty list, a list with all duplicates, and a list with no duplicates. The implementation handles an empty list by returning an empty list immediately. For a list with all duplicates, the output will contain only one element, while a list with no duplicates will return the original list.

To ensure the solution works correctly, we can test it with various cases:
1. Input: `[1, 1, 2, 3, 3]` → Output: `[1, 2, 3]`
2. Input: `[]` → Output: `[]`
3. Input: `[1, 2, 3]` → Output: `[1, 2, 3]`
4. Input: `[1, 1, 1]` → Output: `[1]`
These tests cover normal cases, edge cases, and ensure robustness.

Implement Adjacent-Line Uniq

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