Keep the keys with the highest values in a map https://go.dev/play/p/E-PQldhgz4M

ranked_window.go

package main

import "fmt"

func BenchmarkMapIteration(b *testing.B) {

	size := 1000
	ranked := make(map[int]uint8, size)
	for i := 1; i < size; i++ {
		ranked[i] = uint8(i % 8)
	}

	// We have a fixed-size "ranked" map which we want to keep only the "highest" values in
	// So, as new values come along we loop through the whole array to see if something lower exists we can
	// remove and replace with the new value

	var changes int
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		key := i + size
		value := uint8(i % 8)

		sK, sV := -1, value
		for k, v := range ranked {
			if v < sV {
				sK = k
				sV = v
			}
		}

		// Found something smaller? Remove it and add this
		if sK != -1 {
			changes++
			delete(ranked, sK)
			ranked[key] = value
		}

	}

	b.Logf("%d keys left, %d changes\n", len(ranked), changes)
}