From 9f02bcd63d21adcc0aa2d6e617155d12a3837075 Mon Sep 17 00:00:00 2001
From: Chen-Wang-JY <75002576+Chen-Wang-JY@users.noreply.github.com>
Date: Sun, 23 May 2021 15:58:26 +0800
Subject: [PATCH] =?UTF-8?q?Update=200017.=E7=94=B5=E8=AF=9D=E5=8F=B7?=
 =?UTF-8?q?=E7=A0=81=E7=9A=84=E5=AD=97=E6=AF=8D=E7=BB=84=E5=90=88.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 problems/0017.电话号码的字母组合.md | 35 +++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

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 f06ed80a..b35780ae 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
@@ -281,7 +281,40 @@ class Solution {
 }
 ```
 
-Python：
+Python3：
+```Python3
+class Solution:
+    ans = []
+    s = ''
+    letterMap = {
+        '2': 'abc',
+        '3': 'def',
+        '4': 'ghi',
+        '5': 'jkl',
+        '6': 'mno',
+        '7': 'pqrs',
+        '8': 'tuv',
+        '9': 'wxyz'
+    }
+
+    def letterCombinations(self, digits):
+        self.ans.clear()
+        if digits == '':
+            return self.ans
+        self.backtracking(digits, 0)
+        return self.ans
+
+    def backtracking(self, digits, index):
+        if index == len(digits):
+            self.ans.append(self.s)
+            return
+        else:
+            letters = self.letterMap[digits[index]]  # 取出数字对应的字符集
+            for letter in letters:
+                self.s = self.s + letter  # 处理
+                self.backtracking(digits, index + 1)
+                self.s = self.s[:-1]      # 回溯
+```
 
 
 Go：