@requires_authorization

@author johnsondu

@create_time 2015.7.22 18:58

@url [remove dublicates from sorted array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/)

/**

 * @description: 从有序数组中剔除元素，最多常量额外空间，设置标兵依次比較

 * @time_complexity： O(n)

 * @space_complexity: O(1)

 */

class Solution {

public:

    int removeDuplicates(vector<int>& nums) {

        const int len = nums.size();

        if(len < 2) return len;

        int first = nums[0];

        int idx = 1;

        for(int i = 1; i < len; i ++) {

            if(nums[i] == first) continue;

            else {

                first = nums[i];

                nums[idx] = first;

                idx ++;

            }

        }

        return idx;

    }

};