#include <vector>

using namespace std;
void FindPair(vector<int> arr,int n,vector<int>& answer,int maxsize);

vector<int> solution(vector<int> arr)
{
    vector<int> answer;
    FindPair(arr,0,answer,arr.size());
    return answer;
}

void FindPair(vector<int> arr,int n,vector<int>& answer,int maxsize)
{
    if(n + 1 <= maxsize)
    {
        if(n + 1 == maxsize || arr.at(n) != arr.at(n + 1))
            answer.push_back(arr.at(n));
        
        FindPair(arr,n + 1,answer,maxsize);
    }
}


findpair의 if문 하나만 없애면 될거같은데 더이상 생각이 안남 아