Find median of merged RLE arrays

## Problem You are given two **run-length encoded (RLE)** arrays `A` and `B`. Each is sorted by `value` in non-decreasing order. - Each element is a pair `(value, frequency)` meaning `value` appears `frequency` times in the underlying uncompressed array. - Let `UA` be the uncompressed array represented by `A`, and `UB` similarly for `B`. - Consider the fully merged multiset/array `U = sort(UA ∪ UB)` (i.e., as if you uncompressed both arrays and merged them into one sorted array). Return the **median** of `U`. ## Median Definition Let `N = len(U)`. - If `N` is odd, the median is `U[N//2]` (0-indexed). - If `N` is even, the median is `(U[N//2 - 1] + U[N//2]) / 2`. ## Constraints / Requirements - `frequency` values may be very large, so you must **not** explicitly uncompress the arrays. - `A` and `B` are individually sorted by `value`. ## Example `A = [(1, 2), (5, 1)]` represents `[1, 1, 5]` `B = [(2, 3)]` represents `[2, 2, 2]` Merged: `[1, 1, 2, 2, 2, 5]` → median is `(2 + 2) / 2 = 2`