题目
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.
解题思路
将当前的结果与新的数字所对应的字符进行拓展
代码
class Solution:
def letterCombinations(self, digits: str) -> List[str]:
if not digits:
return []
dic = {'2':"abc", '3':"def", '4':"ghi", '5':"kjl", '6':"mno", '7':"pqrs", '8':"tuv", '9':"wxyz"}
res = [c for c in dic[digits[0]]]
for d in digits[1:]:
res = [i + c for i in res for c in dic[d]]
return res
