Rendezvous Hash Pick

Problem

Choose a node for a key with the rendezvous (highest random weight) hashing scheme.

For each node compute the djb2 hash of the string "node:key" and pick the node with the largest score, breaking ties by the lexicographically smallest node name. The djb2 hash starts at 5381 and updates h = (h * 33 + ord(ch)) mod 2**32.

Return the chosen node, or None for an empty node list.

Hint

Scanning nodes in sorted order with a strict greater-than comparison makes ties deterministic.

Test cases

case 1

in: [["a","b","c"],"x"]

expected: "c"

case 2

in: [["n1","n2","n3"],"user42"]

expected: "n1"

case 3

in: [["only"],"k"]

expected: "only"

case 4

in: [[],"k"]

expected: null

Starter codePython

def rendezvous_hash(nodes, key):
    # Your code here
    pass

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