80. Remove Duplicates from Sorted Array II

Remove Duplicates from Sorted Array II

Follow up for “Remove Duplicates”:
What if duplicates are allowed at most twice?

For example,
Given sorted array nums = [1,1,1,2,2,3],

Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3. It doesn’t matter what you leave beyond the new length.

Like what we have learned in Remove Duplicates from Sorted Array, now

I write down universal code for allowing duplicates once, twice or more after removement.

NOW ATTENTION PLEASE:

Given a sorted array numbers, how can we remove duplicate elements in this array, what if duplicates are allowed at most once, twice or more?

Note that, if the array is not sorted, just one variable is not enough; hashmap will be needed to record the times.

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        if(nums.size() < 2) return nums.size();

        int index = 2;

        for(int i = 2; i < nums.size(); ++i){
            if(nums[i] != nums[index -2]){
                nums[index++] = nums[i];
            }
        }
        return index;
    }
};

Conclusion

1.Sorted array

2.Remove duplicate elements

3.the at most times of duplicate elements