Remove Consecutive Duplicates 🎯

Welcome to another exciting lesson on Data Structures and Algorithms! Today, we're going to learn how to remove consecutive duplicates from a list or an array. This is a common problem you might encounter in various real-world scenarios, such as cleaning datasets or optimizing your code. Let's dive in!

Understanding the Problem 📝

Given a list or an array, our goal is to remove all consecutive duplicate elements and return the resulting list or array.

Here's an example to illustrate the problem:

Input: [1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 6, 6, 7]
Output: [1, 2, 3, 4, 5, 6, 7]

Algorithm 💡

To solve this problem, we can use a combination of loops and conditional statements. The basic idea is to iterate through the list or array and compare each element with the next one. If the current element is the same as the next one, we skip it; otherwise, we add it to the result list.

Here's a Python example:

python

def remove_consecutive_duplicates(lst):
    result = []
    for i in range(len(lst)):
        if i == 0 or lst[i] != lst[i-1]:
            result.append(lst[i])
    return result

# Test the function
numbers = [1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 6, 6, 7]
print(remove_consecutive_duplicates(numbers))

Analysis 📝

Time Complexity: O(n) - We iterate through the list once, so the time complexity is linear to the size of the list.
Space Complexity: O(n) - We store the result in a new list, so the space complexity is linear to the size of the result list, which could be smaller than the input list.

Quiz Time 🎯

Advanced Example 💡

In a real-world project, you might encounter a more complex version of this problem, where you need to remove consecutive duplicates while preserving the order of the unique elements. Here's a Python example that achieves this using the itertools module:

python

from itertools import groupby

def remove_consecutive_duplicates_preserve_order(lst):
    return list(groupby(lst))

# Test the function
numbers = [1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 6, 6, 7]
print(list(remove_consecutive_duplicates_preserve_order(numbers)))

Summary 📝

In this lesson, we learned how to remove consecutive duplicates from a list or an array using Python. We also discussed the time and space complexity of the algorithm and explored an advanced example that preserves the order of unique elements.

By understanding and mastering this concept, you'll be well-equipped to handle similar problems in your programming journey. Happy coding! 🚀