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