Abbasss's blog

By Abbasss, history, 4 hours ago, In Russian

A Segment Tree (дерево отрезков) is a binary tree data structure used to store information about array intervals and answer range queries or update values very quickly. 1, 2, 3What is it used for?Range queries: Find the sum, minimum, or maximum value in a subarray a[l...r].Updates: Change an element or a whole range of elements.Speed: Both queries and updates run in (O(\log n)) time. 1, 2How does it work?Root node: Represents the entire array (from index 0 to n-1).Child nodes: Split the range in half (left child takes the first half, right child takes the second half).Leaf nodes: Represent single elements of the original array.Principle: It uses a divide-and-conquer approach. To answer a query for a big range, you combine pre-calculated answers from smaller, perfectly fitting segments in the tree. 1You can read a detailed introductory guide on GeeksforGeeks Segment Tree or check the Segment Tree Wikipedia page for formal definitions. 1, 2If you'd like, let me know:Do you want to see a code example (in C++, Python, or Java)?Do you need an explanation of range updates and lazy propagation?

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