2215. Find the Difference of Two Arrays

class Solution {
public:
    vector<vector<int>> findDifference(vector<int>& nums1, vector<int>& nums2) {
        sort(nums1.begin(), nums1.end());
        sort(nums2.begin(), nums2.end());
        int n = nums1.size(), m = nums2.size();

        int i=0, j=0;
        set<int> n1, n2;

        while(i<n || j<m)
        {
            if(i<n && j<m)
            {
                if(nums1[i]<nums2[j])
                {
                    n1.insert(nums1[i]);
                    i++;
                }
                else if(nums1[i]>nums2[j])
                {
                    n2.insert(nums2[j]);
                    j++;
                }
                else
                {
                    int k = j;
                    while( j < m && nums1[i] == nums2[j])
                    {
                        j++;
                    }
                    while(i<n && nums1[i] == nums2[k])
                    {
                        i++;
                    }
                    
                }
            }
            else if(i<n)
            {
                n1.insert(nums1[i]);
                i++;
            }
            else
            {
                n2.insert(nums2[j]);
                j++;
            }
        }

        vector<int> a;
        vector<int> b;

        for(auto &val : n1)
        {
            a.push_back(val);
        }

        for(auto &val : n2)
        {
            b.push_back(val);
        }

        return {a,b};
    }
};