전화번호 목록

#include <string>
#include <vector>
#include <algorithm>
using namespace std;

bool solution(vector<string> phone_book) 
{
    bool answer = true;
    
    sort(phone_book.begin(), phone_book.end());
    for(int i = 0; i < phone_book.size() - 1; i++)
    {
        if (phone_book[i] == phone_book[i+1].substr(0, phone_book[i].size()))
        {
            return false;
        }
    }
    
    return answer;
}