Calculate Partition in Go

partition.go

package main

import "fmt"
import "sort"

type EMPTY struct {}

var PRESENT EMPTY = EMPTY{}

func partition(val int) []string {
	set := make(map[string]EMPTY)
	for i := 1; i<=val;i++ {
		for _,result := range worker([]int{i},val-i) {
			set[fmt.Sprintf("%v",result)]=PRESENT
		}
	}
	out := make([]string,len(set))
	pos :=0
	for key := range set {
		out[pos] = key
		pos++
	}
	sort.Strings(out)
	return out
}

func worker(already []int, val int) [][]int {
	if val == 0 {
		sort.Ints(already)
		return [][]int{already}
	}
	out := [][]int {}
	for i := 1;i<=val;i++ {
		out = append(out,worker(append(already,i),val-i)...)
	}
	return out
}

func main() {
	for i := 0;i<10;i++ {
		result := partition(i)
		fmt.Printf("%d (%d): %v\n",i,len(result),result)
	}
}