80. 删除有序数组中的重复项 II

方法一

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        int len = 0;
        for(auto num : nums)
            if(len < 2 || nums[len-2] != num)
                nums[len++] = num;
        return len;
    }
};

方法二

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

        int fast = 2, slow = 2;
        while(fast < numsLength){
            if(nums[slow - 2] != nums[fast]){
                nums[slow] = nums[fast];
                slow++;
            }
            fast++;
        }

        return slow;
    }
};