Formando equipo

///Link del enunciado http://juez.oia.unsam.edu.ar/#/task/equipo/statement

#include <iostream>
#include <vector>
#include <map>
#include <fstream>

using namespace std;

pair <int, string> best;

struct Trie{
    map < char, pair <int, Trie> > arbol;

    int nivel = -1;
};

void armar(Trie &T, const string &s, const int &p){
    if(p < int(s.size() + 1)){
        T.arbol[s[p]].first++;

        T.nivel = ((p < int(s.size())) ? (p + 1) : p);

        armar(T.arbol[s[p]].second, s, (p + 1));
    }
}

void recorrer(Trie &T, const string &s){
    for(auto i:T.arbol){
        int o = (i.second.first * (T.nivel * T.nivel));

        if(o > best.first) best = {o, (s + i.first)};

        recorrer(i.second.second, (s + i.first));
    }
}

int main()
{
    ifstream in("equipo1.in", fstream::in);
    ofstream out("equipo.out", fstream::out);

    int fil, col;

    Trie T;

    in >> col >> fil;

    for(int i = 0; i < fil; i++){
        string s;

        in >> s;

        armar(T, s, 0);
    }

    recorrer(T, "");

    out << best.first << endl << best.second << endl;

    in.close();
    out.close();

    return 0;
}