Update next-closest-time.py

Author: kamyu104

Python/next-closest-time.py

@@ -1,6 +1,27 @@
 # Time:  O(1)
 # Space: O(1)
 
+# Given a time represented in the format "HH:MM",
+# form the next closest time by reusing the current digits.
+# There is no limit on how many times a digit can be reused.
+#
+# You may assume the given input string is always valid.
+# For example, "01:34", "12:09" are all valid. "1:34", "12:9" are all invalid.
+#
+# Example 1:
+#
+# Input: "19:34"
+# Output: "19:39"
+# Explanation: The next closest time choosing from digits 1, 9, 3, 4, is 19:39, which occurs 5 minutes later.
+# It is not 19:33, because this occurs 23 hours and 59 minutes later.
+#
+# Example 2:
+#
+# Input: "23:59"
+# Output: "22:22"
+# Explanation: The next closest time choosing from digits 2, 3, 5, 9, is 22:22.
+# It may be assumed that the returned time is next day's time since it is smaller than the input time numerically.
+
 class Solution(object):
     def nextClosestTime(self, time):
         """