Create count-hills-and-valleys-in-an-array.py

Author: kamyu104

Python/count-hills-and-valleys-in-an-array.py

@@ -0,0 +1,19 @@
+# Time:  O(n)
+# Space: O(1)
+
+# simulation, array
+class Solution(object):
+    def countHillValley(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        result, inc = 0, -1
+        for i in xrange(len(nums)-1):
+            if nums[i] < nums[i+1]:
+                result += int(inc == 0)
+                inc = 1
+            elif nums[i] > nums[i+1]:
+                result += int(inc == 1)
+                inc = 0
+        return result