feat: add python solution to lc problem: No.0941 (doocs#686)

No.0941.Valid Mountain Array

Author: AshwinSolanki76

solution/0900-0999/0941.Valid Mountain Array/README.md

@@ -66,7 +66,17 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def validMountainArray(self, arr: List[int]) -> bool:
+        n = len(arr)
+        if n < 3:
+            return False
+        l, r = 0, n - 1
+        while l + 1 < n - 1 and arr[l] < arr[l + 1]: 
+            l += 1
+        while r - 1 > 0 and arr[r] < arr[r - 1]: 
+            r -= 1
+        return l == r
 ```
 
 ### **Java**

solution/0900-0999/0941.Valid Mountain Array/README_EN.md

@@ -44,7 +44,17 @@
 ### **Python3**
 
 ```python
-
+class Solution:
+    def validMountainArray(self, arr: List[int]) -> bool:
+        n = len(arr)
+        if n < 3:
+            return False
+        l, r = 0, n - 1
+        while l + 1 < n - 1 and arr[l] < arr[l + 1]: 
+            l += 1
+        while r - 1 > 0 and arr[r] < arr[r - 1]: 
+            r -= 1
+        return l == r
 ```
 
 ### **Java**

solution/0900-0999/0941.Valid Mountain Array/Solution.py

@@ -0,0 +1,11 @@
+class Solution:
+    def validMountainArray(self, arr: List[int]) -> bool:
+        n = len(arr)
+        if n < 3:
+            return False
+        l, r = 0, n - 1
+        while l + 1 < n - 1 and arr[l] < arr[l + 1]: 
+            l += 1
+        while r - 1 > 0 and arr[r] < arr[r - 1]: 
+            r -= 1
+        return l == r