Create valid-mountain-array.py

Author: kamyu104

Python/valid-mountain-array.py

@@ -0,0 +1,16 @@
+# Time:  O(n)
+# Space: O(1)
+
+class Solution(object):
+    def validMountainArray(self, A):
+        """
+        :type A: List[int]
+        :rtype: bool
+        """
+        i = 0
+        while i+1 < len(A) and A[i] < A[i+1]:
+            i += 1
+        j = len(A)-1
+        while j-1 >= 0 and A[j-1] > A[j]:
+            j -= 1
+        return 0 < i == j < len(A)-1