80. Remove Duplicates from Sorted Array II

[LeetCode] 80. Remove Duplicates from Sorted Array II

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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.

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把有序數組中次數超過2的元素多餘的去掉，保證每個元素不超過2次重複。

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class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        int len = nums.size();
        if (len == 0) return 0;
        int cnt = 1;
        int last = nums[0];
        vector<int> res(1, last);
        for (int i=1; i<len; ++i) {
            if (nums[i] == last) {
                cnt += 1;
                if (cnt > 2) continue;
            } else {
                cnt = 1;
                last = nums[i];
            }
            res.push_back(nums[i]);
        }
        nums = res;
        return res.size();
    }
};