Use a double pointer to delete duplicates in an ordered array

class Solution {
    
    
    public int removeDuplicates(int[] nums) {
    
    
        if(nums.length==0) return 0;
        int i=0;
        for(int j=1;j<nums.length;j++){
    
    
            if(nums[i]!=nums[j]){
    
    
                nums[++i]=nums[j];
            }
        }
        return i+1;
    }
}