package main

import "fmt"
import "os"
import "strconv"

const HOLE = 0
const BOARD_DIM = 4
const BOARD_SIZE = BOARD_DIM * BOARD_DIM

type Space int8
type Board [BOARD_SIZE]Space

const (
	LEFT  = -1
	RIGHT = +1
	UP    = -BOARD_DIM
	DOWN  = +BOARD_DIM
)

func read_board_from_strings(in []string) (*Board, error) {
	if len(in) != BOARD_SIZE {
		return nil, fmt.Errorf("Please provide %d values", BOARD_SIZE)
	}
	var b Board
	for i, s := range in {
		num, err := strconv.Atoi(s)
		b[i] = Space(num)
		if err != nil {
			return nil, err
		}
	}
	return &b, nil
}

func adjacent_spaces(s Space) []Space {
	if s < 0 || s >= BOARD_SIZE {
		panic("Invalid space")
	}
	var adjacent []Space
	if s >= BOARD_DIM {
		adjacent = append(adjacent, s+UP)
	}
	if s < BOARD_SIZE-BOARD_DIM {
		adjacent = append(adjacent, s+DOWN)
	}
	if s%BOARD_DIM != 0 {
		adjacent = append(adjacent, s+LEFT)
	}
	if s%BOARD_DIM != BOARD_DIM-1 {
		adjacent = append(adjacent, s+RIGHT)
	}
	return adjacent
}

func main() {
	start, err := read_board_from_strings(os.Args[1:])
	if err != nil {
		panic(err)
	}
	fmt.Println(start)
}