import java.util.*;
public class Main
{
	public static void main(String[] args) {
	    Solution obj = new Solution();
	    int[] arr = {1,1,1,2,2,3};
	    obj.removeDuplicates(arr);
		System.out.println(Arrays.toString(arr));
	}
}
 
class Solution {
    public int removeDuplicates(int[] nums) {
        int k = 1;
        int count = 1;
        for(int i = 2; i < nums.length; i++){
            if(nums[i] != nums[i-2]){
                nums[++k] = nums[i];
                count++;
            }
        }
 
        return count;
    }
}

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