From d1e96301933881b0b7e7e14a6aeab804a32a9a64 Mon Sep 17 00:00:00 2001
From: Wen <wenslife@outlook.com>
Date: Thu, 26 Aug 2021 13:20:47 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BC=98=E5=8C=96=200027.=E7=A7=BB=E9=99=A4?=
 =?UTF-8?q?=E5=85=83=E7=B4=A0.md=20Python3=E8=A7=A3=E6=B3=95?=
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---
 problems/0027.移除元素.md | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/problems/0027.移除元素.md b/problems/0027.移除元素.md
index fadd4d7e..6fce4c6e 100644
--- a/problems/0027.移除元素.md
+++ b/problems/0027.移除元素.md
@@ -144,15 +144,28 @@ class Solution {
 
 Python：
 
-```python
+```python3
 class Solution:
-    def removeElement(self, nums: List[int], val: int) -> int:
-        i,n = 0,len(nums)
-        for j in range(n):
-            if nums[j] != val:
-                nums[i] = nums[j]
-                i += 1
-        return i
+    """双指针法
+    时间复杂度：O(n)
+    空间复杂度：O(1)
+    """
+
+    @classmethod
+    def removeElement(cls, nums: List[int], val: int) -> int:
+        fast = slow = 0
+
+        while fast < len(nums):
+
+            if nums[fast] != val:
+                nums[slow] = nums[fast]
+                slow += 1
+
+            # 当 fast 指针遇到要删除的元素时停止赋值
+            # slow 指针停止移动, fast 指针继续前进
+            fast += 1
+
+        return slow
 ```