Even-Odd Partition in Go

even_first.go

package main

import "fmt"
import "math/rand"
import "time"

func main() {
	rand.Seed(time.Now().UnixNano())
	vals := rand.Perm(10)
	fmt.Println(vals)
	makeEvenFirst(vals)
	fmt.Println(vals)
}

func makeEvenFirst(vals []int) {
	back := nextBack(len(vals)-1, vals)
	for i := 0; i < back; i++ {
		v := vals[i]
		fmt.Println(v)
		if v%2 != 0 {
			fmt.Printf("swapping %d and %d\n", v, vals[back])
			vals[i] = vals[back]
			vals[back] = v
			back = nextBack(back-1, vals)
		}
	}
}

func nextBack(back int, vals []int) int {
	for back > 0 {
		if vals[back]%2 != 0 {
			back--
		} else {
			break
		}
	}
	return back
}