equalizeArray Hackerrank

int equalizeArray(vector<int> arr) {
    map<int, int > mp ;
    for (int i=0 ;i<arr.size();i++){
        mp[arr[i]]++ ;
    }
    int maxVal=-1 ;
    for (auto x: mp){
        if ( x.second >maxVal ){
            maxVal = x.second ;
        }
    }
    return arr.size()  - maxVal ;
}