Huffman Tree that made me Cuff Rage

#include <bits/stdc++.h>

using namespace std;

ifstream in("t.in");
ofstream out("t.out");

unordered_map<char, int> M;

struct Node
{
    string simbol;
    int freq;
    Node* left_child;
    Node* right_child;
    Node(string c, int x)
    {
        simbol = c;
        freq = x;
        left_child = right_child = NULL;
    }
    ~Node()
    {
        cout <<"destructor apelat!\n";
    }
};

class greaterr
{
public:
    bool operator()(Node* first, Node* second) const
    {
        return first -> freq > second -> freq;
    }
};

vector<pair<string, string>> A;

void Traversal(Node* nod, string bins)
{
    // cout << depth << '\n';
    if(nod -> left_child)
    {
        Traversal(nod -> left_child, bins + "0");
    }
    if(nod -> right_child)
    {
        Traversal(nod -> right_child, bins + "1");
    }
    if(!nod -> left_child && !nod -> right_child)
    {
        A.push_back({nod -> simbol, bins});
        delete nod;
    }
}

int main()
{
    string S;
    getline(in, S);
    for(int i = 0; i < (int)S.size(); ++i)
        M[S[i]]++;
    priority_queue<Node*, vector<Node*>, greaterr> Q;
    Node* nod;
    for(auto i : M)
    {
        string c;
        c += i.first;
        nod = new Node(c, i.second);
        Q.push(nod);
    }

    Node *left, *right, *father;
    while(Q.size() > 1)
    {
        left = Q.top();
        Q.pop();
        right = Q.top();
        Q.pop();
        father = new Node("", left -> freq + right -> freq);
        father -> left_child = left;
        father -> right_child = right;
        Q.push(father);
    }
    Node* Tata = Q.top();
    string bins = "";
    Traversal(Tata, bins);
    for(auto i : A)
    {
        out << i.first << " " << i.second << '\n';
    }
    return 0;
}