Delta CRDT Compression

Problem

Compress a list of CRDT updates to the latest version per key.

updates is a list of [key, value, version]. Keep only the update with the largest version for each key.

Return [key, value, version] triples sorted by key.

Hint

Version numbers give a total order per key, so the maximum version wins.

case 1

in: [[["a",1,1],["b",2,1],["a",3,2]]]

expected: [["a",3,2],["b",2,1]]

case 2

in: [[]]

expected: []

case 3

in: [[["x",5,7]]]

expected: [["x",5,7]]

case 4

in: [[["k",1,2],["k",1,1]]]

expected: [["k",1,2]]

Starter codePython

def delta_compress(updates):
    # Your code here
    pass

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