Remove Duplicates from Sorted Array II

問題描述

Follow up for 」Remove Duplicates」: What if duplicates are allowed at most twice? For example, Given sorted array A = [1,1,1,2,2,3], Your function should return length = 5, and A is now [1,1,2,2,3]

myCode

/*
 * 對一個已經有序的序列進行重複元素刪除
 * 即保證序列相同元素最多出現兩次
*/
class Solution1
{
public:
    int removeDuplicatesFromSortedArray(vector<int>& nums)
    {
        //當序列爲空時
        if(nums.size() <= 2)
            return nums.size();

        //當序列非空時
        int index = 2;
        for(int i = 2;i<nums.size();i++)
        {
            if(nums[i] != nums[index-2])
            {

                nums[index] = nums[i];
                index++;
            }
        }
        return index;
    }
};

測試代碼

#include<iostream>
#include<vector>
using namespace std;
/*
 * 對一個已經有序的序列進行重複元素刪除
 * 即保證序列相同元素最多出現兩次
*/
class Solution1
{
public:
    int removeDuplicatesFromSortedArray(vector<int>& nums)
    {
        //當序列爲空時
        if(nums.size() <= 2)
            return nums.size();

        //當序列非空時
        int index = 2;
        for(int i = 2;i<nums.size();i++)
        {
            if(nums[i] != nums[index-2])
            {

                nums[index] = nums[i];
                index++;
            }
        }
        return index;
    }
};

//主函數
int main(void)
{

    vector<int> a;
    a.push_back(1);
    a.push_back(1);
    a.push_back(1);
    a.push_back(2);
    a.push_back(2);
    a.push_back(3);
    a.push_back(4);
    a.push_back(4);
    a.push_back(4);
    a.push_back(4);
    a.push_back(5);

    int index = a.size();
    //在刪除重複元素以前
    cout<<"before:"<<endl;
    for(int i = 0;i<index;i++)
    {
        cout<<a[i]<<" ";
    }

    cout<<endl;

    //刪除重複元素以後
    Solution1 s;
    int return_num = s.removeDuplicatesFromSortedArray(a);
    cout<<"after:"<<endl;
    for(int i = 0;i<return_num;i++)
    {
        cout<<a[i]<<" ";
    }
    cout<<endl;
    return 0;
}