class Solution{
    public: 
        int removeDuplicates(vector<int> & nums){
            if(nums.empty()) return 0;
            int i =1;
            for(int j =1;j<nums.size();j++){
                if(nums[j]!=nums[i-1]){
                        nums[i] = nums[j];
                        i++;
                }
            }
            return i;

        }
};

//TC : O(n)
//SC: O(1)

/* InPlace algorithm : An algorithm that modifies the input data directly, uses constant space o(1). Here We traverse the sorted array and keep only unique elements by overwriting duplicates in-place.
Whenever a new (different) element is found, we place it at the next available position.
The final count of unique elements is returned.
i -> marks the position where the next unique element should be stored
j-> scans the array to find new elements
*/