A segment tree is a binary tree used for storing intervals, allowing you to perform range queries like sum, minimum, or maximum in logarithmic time. It's particularly useful when you need to answer multiple queries on an array, such as finding the sum of elements within a given range or the minimum value in a subarray, especially when the array is being updated frequently. In TypeScript, you can implement a segment tree by constructing a binary tree where each node represents a range of the array, and the value of the node is the result of a query operation (e.g., sum, minimum, maximum) on that range. Building the segment tree requires O(n) time, and each query or update operation is handled in O(log n) time. The segment tree can be used in applications like dynamic range queries, game development, and database indexing. By understanding how to build and use a segment tree, you can optimize operations that involve frequent updates and queries on large datasets.