[리트코드/Leetcode] 17 - Letter Combinations of a Phone Number

17 - Letter Combinations of a Phone Number

📌 문제

Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order.

A mapping of digit to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters.

📋 코드

from itertools import product

class Solution:
    def letterCombinations(self, digits: str) -> List[str]:
        number = [[], [], ['a', 'b', 'c'], ['d', 'e', 'f'], ['g', 'h', 'i'],
                  ['j', 'k', 'l'], ['m', 'n', 'o'], ['p', 'q', 'r', 's'],
                  ['t', 'u', 'v'], ['w', 'x', 'y', 'z']]

        if not digits:
            return []

        digit = list(map(int, digits))
        select = []
        for d in digit:
            select.append(number[d])

        prod = list(product(*select))
        result = []
        for char in prod:
            tmp = ""
            for c in char:
                tmp += c
            result.append(tmp)

        return result

💡 한마디

두 개 이상 리스트의 조합을 구하고자 할 때에는 product를 이용하자 !