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