Create average-waiting-time.py

Author: kamyu104

Python/average-waiting-time.py

@@ -0,0 +1,14 @@
+# Time:  O(n)
+# Space: O(1)
+
+class Solution(object):
+    def averageWaitingTime(self, customers):
+        """
+        :type customers: List[List[int]]
+        :rtype: float
+        """
+        avai = wait = 0.0
+        for a, t in customers:
+            avai = max(avai, a)+t
+            wait += avai-a
+        return wait/len(customers)