```go
package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
	"strings"
)

type Boy struct {
	id    int
	skill int
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1024*1024), 1024*1024*10)

	if !scanner.Scan() {
		return
	}
	n, _ := strconv.Atoi(scanner.Text())

	boys := make([]Boy, n)
	for i := 0; i < n; i++ {
		scanner.Scan()
		skill, _ := strconv.Atoi(scanner.Text())
		boys[i] = Boy{id: i + 1, skill: skill}
	}

	sort.Slice(boys, func(i, j int) bool {
		return boys[i].skill > boys[j].skill
	})

	team1 := make([]string, 0, n/2+1)
	team2 := make([]string, 0, n/2+1)
	for i, b := range boys {
		if i%2 == 0 {
			team1 = append(team1, strconv.Itoa(b.id))
		} else {
			team2 = append(team2, strconv.Itoa(b.id))
		}
	}

	out := bufio.NewWriter(os.Stdout)
	fmt.Fprintln(out, len(team1))
	fmt.Fprintln(out, strings.Join(team1, " "))
	fmt.Fprintln(out, len(team2))
	fmt.Fprintln(out, strings.Join(team2, " "))
	out.Flush()
}
```