Time-Based Key-Value Store

Problem

Simulate a time-based key-value store.

operations contains "set" (keys[i], values[i] at timestamps[i]) or "get" (return the value for keys[i] at the largest timestamp less than or equal to timestamps[i]). Sets for the same key are performed with non-decreasing timestamps.

Return the list of recorded results (None for set, a string for get; "" when no value qualifies).

Hint

Appending (timestamp, value) pairs keeps each key's history sorted, and the last qualifying entry wins.

Test cases

case 1

in: [["set","set","get","get","get"],["foo","foo","foo","foo","foo"],["bar","bar2","","",""],[1,4,1,4,5]]

expected: [null,null,"bar","bar2","bar2"]

case 2

in: [["set","get"],["a","b"],[1,""],[10,5]]

expected: [null,""]

case 3

in: [["get"],["x"],[""],[0]]

expected: [""]

case 4

in: [["set","set","get","get"],["k","k","k","k"],[1,2,"",""],[5,5,5,6]]

expected: [null,null,2,2]

Starter codePython

def time_map_ops(operations, keys, values, timestamps):
    # Your code here
    pass

4 test cases · run your code against them in the editor