# Efficiently Search Sorted Lists with Binary Search Algorithm in Python

In the world of computer science, algorithms play a crucial role in helping programmers solve complex problems. One such algorithm is the Binary Search Algorithm.

In this article, we will explore what Binary Search Algorithm is, how it works, and how to implement it in Python. So, buckle up, and let’s get started.

## 1) Binary Search Algorithm

What is Binary Search Algorithm? The Binary Search Algorithm is a searching algorithm that compares the middle element of a sorted list with the target value being searched.

If the middle element matches the target value, the search is over, and the element is found. If the middle element is greater than the target value, the search continues in the left half of the list.

If the middle element is smaller than the target value, the search continues in the right half of the list. The process continues until the target value is either found or not found.

## Example of Binary Search Algorithm in action

Let’s take an example to understand the Binary Search Algorithm better. Imagine you have a dictionary with thousands of pages, and you want to find the word “book.” You can start your search from the center of the dictionary and see if the word “book” is on that page.

If it is, the search is over. If not, you can eliminate half of the dictionary, either by going to the left or the right, based on whether “book” comes before or after the current page.

You repeat this process until you find the word “book.”

## How to implement Binary Search Algorithm in Python

Let’s now explore how we can use Python to implement Binary Search Algorithm. We will write a function that takes three arguments – the sorted list, the starting point, and the ending point, and the target value.

“`

def binary_search(arr, start, end, target):

while start <= end:

mid = (start + end) // 2

if arr[mid] == target:

return mid

elif arr[mid] > target:

end = mid – 1

else:

start = mid + 1

return -1

“`

## Explanation of the code

The first line defines the function “binary_search,” which takes four arguments – the sorted list (arr), the starting point (start), the ending point (end), and the target value (target). We then enter into a while loop, which continues until the start value is less than or equal to the end value.

Inside the loop, we calculate the midpoint by taking the average of the start and end values. We then check whether the middle item of the list is equal to the target value.

If it is, we return the index position. If the middle item is greater than the target value, we update the end value to be one less than the midpoint.

If the middle item is less than the target value, we update the start value to be one greater than the midpoint.

After the while loop, if the target value is not found, we return -1.

## Conclusion

In conclusion, the Binary Search Algorithm is a powerful tool for searching for a target value in a sorted list. It saves time by dividing the search space into half and eliminates half of the search space in each iteration.

Moreover, implementing Binary Search Algorithm in Python is relatively easy and straightforward. So, the next time you need to search a sorted list for a particular value, you know what algorithm to use – the Binary Search Algorithm.

## Comparison with Linear Search Algorithm

When it comes to searching algorithms, one common one is the Linear Search Algorithm. In Linear Search, we iterate through the entire list, checking each item one by one until we find the target value or reach the end of the list.

The time complexity of a linear search algorithm is O(n), which means that the worst-case scenario is that we have to search through all n elements in the list. In contrast, the Binary Search Algorithm divides the search space in half in each iteration, which means that it drastically reduces the search space for each comparison.

This results in a much faster algorithm than Linear Search.

## Time complexity of Binary Search Algorithm

The time complexity of Binary Search Algorithm is O(log 2 n), which means that it has a time complexity that increases logarithmically with the size of the input. This is because, in Binary Search, you cut down the search space in half with every iteration.

Hence, the highest amount of iterations you will have to do to search any array of size n is log 2 n. This can be represented as log base 2 of n, where n is the number of elements in the array.

This efficiency is in contrast to the time complexity of Linear Search, which grows linearly with the size of the input.

## Summary of Binary Search Algorithm

In summary, Binary Search Algorithm is an efficient algorithm that can quickly search for a target value in a sorted list.

It works by dividing the search space in half with each iteration, drastically reducing the search time as compared to Linear Search. The time complexity of this algorithm is O(log 2 n), which means that it scales well with large inputs.

## Importance of time complexity in algorithm design

Efficiency is a critical factor in algorithm design, and Binary Search Algorithm is an excellent example of an efficient algorithm. When dealing with large amounts of data, the difference in time complexity between a less efficient algorithm like Linear Search and more efficient algorithms like Binary Search can be significant.

Understanding the time complexity and implementing efficient algorithms like Binary Search is vital for effectively and efficiently solving complex problems in computer science. In conclusion, Binary Search Algorithm is an essential algorithm in computer science that can be utilized to quickly and efficiently search a sorted list for a target value.

Its efficiency, compared to less efficient algorithms like Linear Search, is due to cutting the search space in half with each iteration, resulting in a time complexity of O(log 2 n). Understanding time complexity and implementing efficient algorithms like Binary Search is crucial for optimizing problem-solving in computer science.

In conclusion, the Binary Search Algorithm is an efficient and powerful algorithm that can quickly search sorted lists for target values. Its time complexity is O(log 2 n), significantly lower than the O(n) time complexity of Linear Search Algorithm.

Knowledge of time complexity and efficient algorithms like Binary Search is crucial in effectively and efficiently solving complex problems in computer science. Therefore, understanding and mastering Binary Search Algorithm is essential for any aspiring developer or data scientist.