ackerman function with memoize

ack.go

package main

import (
	"fmt"
)

type AckParam struct {
	M uint64
	N uint64
}

func main() {
	var (
		cache = make(map[AckParam]uint64)
		ack   func(uint64, uint64) uint64
	)
	ack = func(m, n uint64) uint64 {
		k := AckParam{m, n}
		// /*
		if v, ok := cache[k]; ok {
			return v
		}
		// */
		var result uint64
		switch {
		case m == 0:
			result = n + 1
		case n == 0:
			result = ack(m-1, 1)
		default:
			result = ack(m-1, ack(m, n-1))
		}
		cache[k] = result
		return result
	}
	fmt.Println(ack(4, 1))
}