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 letterCombina..
