#include<iostream>#include<map>using namespace std;class Solution{public:    int singleNumber(int A[],int n)    {        multimap<int,int> mp;        int i;        for(i=0;i<n;i++)        {            mp.insert({A[i],i});        }        auto map_it=mp.begin();        while(map_it!=mp.end())        {            auto fst=map_it;            auto snd=map_it;            fst++;            snd++;            snd++;            if((fst)==mp.end()||snd==mp.end())                return (map_it)->first;            if(map_it->first!=(fst)->first||map_it->first!=snd->first)                break;            map_it++;            map_it++;            map_it++;        }        return map_it->first;    }};int main(){    Solution s;    int arr[]={2,4,2,4,2,4,5,5};    cout<<s.singleNumber(arr,8)<<endl;}