Трай дерево с удалением

#include <iostream>
#include <string>
#include <Windows.h>
#include <vector>
using namespace std;

struct Node
{
    vector<Node*> children;
    vector<size_t> keys;
    char symbol = '+';
};

class TrieTree
{
    Node* root;

    void addMethod(Node* node, const string& word, const size_t& id, const size_t& key) {

        if (id >= word.size())
            return;

        for (size_t j = 0; j < node->children.size(); j++)
            if (node->children[j]->symbol == word[id])
            {
                node->children[j]->keys.push_back(key);
                addMethod(node->children[j], word, id + 1, key);
                return;
            }

        Node* tmp = new Node;
        tmp->symbol = word[id];
        tmp->keys.push_back(key);

        node->children.push_back(tmp);
        addMethod(tmp, word, id + 1, key);

    };
    void removeMethod(Node* node,const size_t& key) {

        for (size_t i = 0; i < node->children.size(); i++)
        {
            for (size_t j = 0; j < node->children[i]->keys.size(); j++)
            {
                if (node->children[i]->keys[j] == key)
                {
                    removeMethod(node->children[i], key);
                    if (node->children[i]->keys.size() != 1)
                        node->children[i]->keys.erase(node->children[i]->keys.begin() + j);
                    else
                        node->children.erase(node->children.begin() + i);
                    return;
                }

            }
        }

    };

    void getByKeyMethod(Node* node, string& word, const size_t& key)
    {
        for (size_t i = 0; i < node->children.size(); i++)
        {
            for (size_t j = 0; j < node->children[i]->keys.size(); j++)
            {
                if (node->children[i]->keys[j] == key)
                {
                    word += node->children[i]->symbol;
                    getByKeyMethod(node->children[i], word, key);
                    return;
                }

            }
        }
    }

public:
    TrieTree()
    {
        root = new Node;
        root->symbol = '-';
    }
    void add(const string& word, const size_t& key)
    {
        addMethod(root, word,0, key);
    }
    void remove(const size_t& key)
    {
        removeMethod(root,key);
    }
    string getByKey(const size_t& key)
    {
        string word;
        getByKeyMethod(root, word, key);
        return word;
    }
};


int main()
{
    SetConsoleCP(1251);
    SetConsoleOutputCP(1251);

    TrieTree a;
    a.add("бобёр", 1);
    a.add("лань", 2);
    a.add("бобровый", 3);
    a.add("боб", 4);
    a.add("красный", 5);
    a.add("краснознамённый", 6);

    cout << endl << "Before: " << endl;
    for (size_t i = 1; i < 7; i++)
    {
        cout << i << "] " << a.getByKey(i) << endl;
    }

    a.remove(4);
    a.remove(6);

    cout << endl << "After: " << endl;
    for (size_t i = 1; i < 7; i++)
    {
        cout << i << "] " << a.getByKey(i) << endl;
    }

    return 0;
};