LWW Map Merge

Problem

Merge two last-write-wins maps.

Each map stores key to [value, timestamp]. For every key the entry with the larger timestamp wins, and ties keep the value from a. Keys are strings.

Return the merged map.

Hint

On a timestamp tie the first map's value is kept for determinism.

case 1

in: [{"x":["a",1],"y":["b",3]},{"x":["c",2],"z":["d",1]}]

expected: {"x":["c",2],"y":["b",3],"z":["d",1]}

case 2

in: [{},{"k":["v",1]}]

expected: {"k":["v",1]}

case 3

in: [{"k":["a",5]},{"k":["b",5]}]

expected: {"k":["a",5]}

case 4

in: [{},{}]

expected: {}

Starter codePython

def lww_merge(a, b):
    # Your code here
    pass

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