PN-Counter Merge

A PN-Counter is a CRDT built from two grow-only vectors:

• P for increments
• N for decrements

To merge two PN-Counters, take the element-wise max of P and N. The counter value is sum(P) - sum(N).

Types

type PNCounter struct {
    P []int
    N []int
}

Function signature

func MergePNCounter(a, b PNCounter) (PNCounter, int)

Example

a = P:[1,0], N:[0,1]
b = P:[0,2], N:[0,0]
merge = P:[1,2], N:[0,1]
value = 2

Constraints

• len(a.P) == len(b.P)
• len(a.N) == len(b.N)
• len(a.P) == len(a.N)
• 0 <= values <= 1_000_000

Notes

• If lengths do not match, return empty counter and value 0.