```
class Solution {
public:
int removeDuplicates(vector<int>& nums) {
auto numsSize = nums.size();
if(numsSize < 1) return 0; // if vector has 0 elements then return
int counter = 0;
for(int i = 0; i < numsSize - 1; i++)
if(nums[i]!= nums[i+1]) nums[counter++] = nums[i];
// since we miss the last element either (1) there was a duplicate like ....5,5 and we iterated over it
// or (2) there was a unique element and we only put one of them like 5,6 --> 5 enters and we miss 6
nums[counter++] = nums[numsSize-1];
return counter;
}
};
```