Leetcode 3187. Peaks in Array

Given an array where a "peak" is an element greater than its immediate neighbors, process up to 1e5 queries that either update a single element or ask for the number of peaks in a subarray. The challenge is to support fast point updates and range peak-count queries (updates only affect a constant local neighborhood), so use a dynamic range-sum structure (e.g., segment tree/Fenwick) over peak indicators.