Leetcode 2499. Minimum Total Cost to Make Arrays Unequal

Given nums1 and nums2, you may swap any two indices in nums1 at cost equal to the sum of their indices; find the minimum total cost to make nums1[i] != nums2[i] for every i (or return -1 if impossible). The core challenge is a weighted swap-optimization under frequency constraints—choosing which indices (including non-conflicting ones) to use in swaps to resolve equalities while minimizing the total index-sum cost.