You are given two integer arrays, array A and array B. Each Array contains 2n elements. For each index i, select a number between Ai and Bi, so that the sum of the selected 2n elements is maximised. Note you will need to select n elements from A and n elememts from B. A and B are unsorted array.

Does anyone know if this is an existing leetcode question (and what the question number is), or any idea how to solve it?