Binary search: how computers think (and how we can learn from them)

Search algorithms are a set of instructions that help you find the right data among a large amount of information. Imagine that you are looking for the right word in a dictionary. You can flip through the pages one by one (linear search), or you can open the dictionary approximately in the middle and figure out where to look next — closer to the beginning or the end. The second way is much smarter and faster.

That's it binary search — one of the most elegant and effective algorithms in computer science.

How binary search works

Binary search works on the principle of “divide and conquer”. If the data sorted, the algorithm divides the array in half and each time discards the half where the desired element is definitely not present.

For example, you are looking for the number 37 in the list from 1 to 100:

1. First you look at the middle — this is 50. → 37 is less than 50, so we are looking in the left half.

2. The middle of the left side is 25. → 37 is greater than 25, we go to the right.

3. The middle of the new part is 37. Found it!

Instead of 100 steps (if you go through one element), you found the number in just 7 comparisons.

Where binary search meets real life

• Dictionaries and phone books - when you open the right letter and quickly find the word.

• Search for prices in the online store — when the filter instantly shows products from 5000 to 10000 rubles.

• Games — binary search can be used to quickly find coordinates, difficulty levels, or suitable items.

• Databases and file systems — to instantly get the desired record without going through all the data.

• Machine learning - to optimize the parameters and find the best values of the functions.

Why is it important to understand binary search?

Understanding this algorithm helps to develop algorithmic thinking — the ability to solve problems by breaking them down into simple steps. In addition, binary search is often asked in interviews — even with junior developers.

And in everyday life, if you learn to think “in binary”, you can save time and effort: do not check everything, but immediately reduce the excess.

Binary search is not just an algorithm, but a philosophy of efficiency. It shows that sometimes, in order to find what you need, you don't need to run forward, but to be able to divide the path in half.

In Codice programming is easy and fun: short lessons, gamification, help from a smart assistant, and training on any device.

And in our Telegram channel — memes, tips, news and bonuses for those who study with a smile.
Join us 💙