Minimum Cost to Make Array Elements Distinct

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"You are given an array of integers. You want to transform it so that every element is distinct. You may apply the following operation any number of times (including zero): * Choose a subarray arr[i..j]. * Within this subarray, keep only the first occurrence of each element, remove all duplicates, and preserve the order of the remaining elements. * The cost of this operation is the number of unique elements in the chosen subarray. Find the minimum total cost needed to make the entire array contain only distinct elements."