전화번호 목록

sort 이용해서 쉽게 풀기

#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++){
        string curr = phone_book[i];
        string next = phone_book[i+1];
        if(curr == next.substr(0,curr.size())) return false;
    }
    return answer;
}

해쉬 이용해서 정석대로 풀기

#include <string>
#include <vector>
#include <unordered_map>

using namespace std;

bool solution(vector<string> phone_book) {
    bool answer = true;
    unordered_map<string,int> hash_map;
    for(int i = 0; i < phone_book.size(); i++)
        hash_map[phone_book[i]] = 1;
    
    for(int i = 0; i < phone_book.size(); i++){
        string curr = "";
        for(int j = 0; j < phone_book[i].size(); j++){
            curr += phone_book[i][j];
            if(hash_map[curr] && curr != phone_book[i]) return false;
        }
    }
    
    return true;
}