HackerRank "No Prefix Set"

Typical Trie usage. But please note that it could be any order of input strings.

#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <iostream>
using namespace std;

class TrieNode {
public:
    // Initialize your data structure here.
    TrieNode() {
        c = ;
        bIsLast = false;
    }
    TrieNode(char vc) {
        c = vc;
        bIsLast = false;
    }
public:
    char c;
    bool bIsLast;
    unordered_map<char, TrieNode*> childMap;
};

class Trie {
public:
    Trie()
    {
        root = new TrieNode();
    }

    ~Trie()
    {
        if (root)
        {
            for(auto kv : root->childMap)
            {
                delete kv.second;
            }
            delete root;
        }
    }

    // Inserts a word into the trie.
    bool insert(string s)
    {
        TrieNode *r = root;
        for (int i = ; i < s.length(); i++)
        {
            if (r->childMap.find(s[i]) == r->childMap.end())
            {
                r->childMap.insert(make_pair(s[i], new TrieNode(s[i])));
            }
            else if (r->childMap[s[i]]->bIsLast)
            {
                return false;
            }

            r = r->childMap[s[i]];
        }
        r->bIsLast = true;
        return r->childMap.empty();
    }

private:
    TrieNode* root;
};

int main()
{
    Trie tr;

    int n; cin >> n;
    vector<string> strs;
    while(n --)
    {
        string str; cin >> str;
        if(!tr.insert(str))
        {
            cout << "BAD SET" << endl;
            cout << str << endl;
            return ;
        }
    }

    cout << "GOOD SET" << endl;
    return ;
}