Leetcode80

Remove Duplicates from Sorted Array II:
Given a sorted array nums, remove the duplicates in-place such that duplicates appeared at most twice and return the new length.
Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
Example 1:
Given 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 respectively.
It doesn’t matter what you leave beyond the returned length.
Example 2:
Given nums = [0,0,1,1,1,1,2,3,3],
Your function should return length = 7, with the first seven elements of nums being modified to 0, 0, 1, 1, 2, 3 and 3 respectively.
It doesn’t matter what values are set beyond the returned length.

Solution:

#include <iostream>
#include <vector>

using namespace std;

class Solution {
private:
    int nextIndex(const vector<int>& nums, int index){

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

        return  nums.size();
    }
public:
    int removeDuplicates(vector<int>& nums) {

        if ( nums.size() == 0)
            return 0;

        int i = 0;
        int j = 0;
        while(j < nums.size()){
            int k = nextIndex(nums, j);
            int len = min(2, k-j);
            for ( int ii = 0; ii < len; ii++){
                nums[i+ii] = nums[j];
            }
            i += len;
            j = k;
        }

        return i;

    }
};

总结： 要想的设置一个辅助函数去解决问题