class Solution {
public:
    int minimumOperations(vector<int>& nums) {
        set<int> s;
        int ret = 0;
        int len = nums.size();
        for (int i = 0; i < len; i++) {
            if (!nums[i]) continue;
            if (s.find(nums[i]) != s.end()) continue;
            ret += 1;
            s.insert(nums[i]);
        }
        return ret;
    }
};