diff --git a/problems/0017.电话号码的字母组合.md b/problems/0017.电话号码的字母组合.md index 1ebf6f49..dfd0e875 100644 --- a/problems/0017.电话号码的字母组合.md +++ b/problems/0017.电话号码的字母组合.md @@ -322,20 +322,20 @@ python3: ```py class Solution: def letterCombinations(self, digits: str) -> List[str]: - self.s = "" res = [] + s = "" letterMap = ["","","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"] - if len(digits) == 0: return res - def backtrack(digits,index): + if not len(digits): return res + def backtrack(digits,index, s): if index == len(digits): - return res.append(self.s) + return res.append(s) digit = int(digits[index]) #将index指向的数字转为int letters = letterMap[digit] #取数字对应的字符集 for i in range(len(letters)): - self.s += letters[i] - backtrack(digits,index + 1) #递归,注意index+1,一下层要处理下一个数字 - self.s = self.s[:-1] #回溯 - backtrack(digits,0) + s += letters[i] + backtrack(digits, index+1, s) #递归,注意index+1,一下层要处理下一个数字 + s = s[:-1] #回溯 + backtrack(digits, 0, s) return res ```