全列挙(DFS版)

main.go

package main

import (
	"fmt"
	"strings"
)

func comb(a []string) [][]string {
	b := make([][]string, 0)

	var fn func([]string, []string)

	fn = func(v []string, c []string) {
		if len(c) == 0 {
			vv := make([]string, len(v))
			copy(vv, v)
			b = append(b, vv)
			return
		}

		fn(append(v), c[0:len(c)-1])
		fn(append([]string{c[len(c)-1]}, v...), c[0:len(c)-1])
	}

	fn([]string{}, a)

	return b
}

func main() {
	a := []string{"a", "b", "c", "d", "e"}
	b := comb(a)
	for i, v := range b {
		fmt.Printf("%0*b:", len(a), i)
		fmt.Println(strings.Join(v, ","))
	}
}