3810. Minimum Operations to Reach Target Array

You are given two integer arrays nums and target, each of length n, where nums[i] is the current value at index i and target[i] is the desired value at index i.

You may perform the following operation any number of times (including zero):

• Choose an integer value x
• Find all maximal contiguous segments where nums[i] == x (a segment is maximal if it cannot be extended to the left or right while keeping all values equal to x)
• For each such segment [l, r], update simultaneously:
  • nums[l] = target[l], nums[l + 1] = target[l + 1], ..., nums[r] = target[r]

Return the minimum number of operations required to make nums equal to target.

class Solution {
public:
    int minOperations(vector<int>& nums, vector<int>& target) {
        unordered_set<int> us;
        for(int i = 0; i < nums.size(); i++) {
            if(nums[i] != target[i]) us.insert(nums[i]);
        }
        return us.size();
    }
};