Leetcode 3239. Minimum Number of Flips to Make Binary Grid Palindromic I

Given an m×n binary matrix, find the minimum number of cell flips so that either every row or every column becomes palindromic (reads the same forwards and backwards). The core challenge is to choose the better of two independent strategies — reconciling symmetric column pairs for rows or symmetric row pairs for columns — and sum the minimal flips needed across those independent index-pair groups.