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Memoization using Golang Generics

Posted on 22 Jun, 2022
Memoization helps save computation of things that have already been computed by saving them for future use. In this example we use golang generics to implement a Memoized() function that can handle use-case.
// Required Go 1.18 or greater
package main
import "fmt"
type FibonacciDef func(int) int
func Memoize[K comparable, T any](fn func(K) T) func(K) T {
// Type K needs to be comparable (and hashable) since we used it as a map Key
// Type T is any type that can act as a map value
cache := make(map[K]T)
return func(n K) T {
if val, ok := cache[n]; ok {
return val
// add to cache if not found
cache[n] = fn(n)
return cache[n]
func main() {
var memoizedFib FibonacciDef
var simpleFib FibonacciDef
memoizedFib = Memoize(func(num int) int {
if num < 2 {
return num
return memoizedFib(num-1) + memoizedFib(num-2)
simpleFib = func(num int) int {
if num < 2 {
return num
return simpleFib(num-1) + simpleFib(num-2)
// takes more than 1 minute to compute