From a90db6e830474a70dd445a77cef578627374ca5e Mon Sep 17 00:00:00 2001
From: SianXiaoCHN <SilverCHN@outlook.com>
Date: Thu, 17 Mar 2022 13:38:45 -0500
Subject: [PATCH] =?UTF-8?q?0941.=E6=9C=89=E6=95=88=E7=9A=84=E5=B1=B1?=
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0941.有效的山脉数组 python3 从原方法更新到双指针方法
---
 problems/0941.有效的山脉数组.md | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/problems/0941.有效的山脉数组.md b/problems/0941.有效的山脉数组.md
index a2444cc1..4b7a978c 100644
--- a/problems/0941.有效的山脉数组.md
+++ b/problems/0941.有效的山脉数组.md
@@ -106,22 +106,15 @@ class Solution {
 ```python
 class Solution:
     def validMountainArray(self, arr: List[int]) -> bool:
-        if len(arr) < 3 :
-            return False
-
-        i = 1
-        flagIncrease = False # 上升
-        flagDecrease = False # 下降
-
-        while i < len(arr) and arr[i-1] < arr[i]:
-            flagIncrease = True
-            i += 1
-
-        while i < len(arr) and arr[i-1] > arr[i]:
-            flagDecrease = True
-            i += 1
-
-        return i == len(arr) and flagIncrease and flagDecrease
+        left, right = 0, len(arr)-1
+        
+        while left < len(arr)-1 and arr[left+1] > arr[left]:
+            left += 1
+        
+        while right > 0 and arr[right-1] > arr[right]:
+            right -= 1
+        
+        return left == right and right != 0 and left != len(arr)-1
 
 ```