class Solution {
public:
    int removeDuplicates(vector<int>& arr) {
        set<int> st ;
        int n = arr.size();
        for(int i=0 ; i < n; i++){
            st.insert(arr[i]);
        }

        int k = st.size();
        int index = 0;
        for(auto it : st){
            arr[index++] = it;
        } 
        return k;
    }
};

https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/

https://takeuforward.org/data-structure/remove-duplicates-in-place-from-sorted-array/