[Programmers] 전화번호 목록

전화번호부에 적힌 전화번호 중, 한 번호가 다른 번호의 접두어인 경우가 있는지 확인

전화번호부에 적힌 전화번호를 담은 배열 phone_book 이 solution 함수의 매개변수로 주어질 때, 
어떤 번호가 다른 번호의 접두어라면 false, 그렇지 않으면 true를 return 하도록 solution 함수를 작성

def solution(phone_book):
    answer = True
    phone_book.sort()
    for i in range(len(phone_book)-1) :
        for j in range(i+1, len(phone_book)) :
            if phone_book[i] == phone_book[j][:len(phone_book[i])] :
                answer = False
                break
    return answer

왜 효율성은 0점일까

네.. 

필요없는 이중문을 했군요

def solution(phone_book):
    answer = True
    phone_book.sort()
    for i in range(len(phone_book)-1) :
        if phone_book[i] == phone_book[i+1][:len(phone_book[i])] :
                answer = False
                break
    return answer