queen nxn

backtrack.go

package queen

import (
	"fmt"
	"time"

	"github.com/hoenirvili/Main/util"
)

// BackTrack is the main function that
// that will execute recursivly
// finding all the possible solutions
func BackTrack(row int) bool {

	if row >= N {
		return true
	}

	for i := 0; i < N; i++ {
		PrintBoard()
		fmt.Println()
		time.Sleep(4 * time.Millisecond)
		util.ClearScr()
		if CheckInstance(i, row) == true {
			Board[i][row] = "Q"
			PrintBoard()
			fmt.Println()
			time.Sleep(70 * time.Millisecond)
			util.ClearScr()
			if BackTrack(row + 1) {
				return true
			}
			Board[i][row] = "."
		}
	}
	return false
}

build.go

package queen

import (
	"fmt"
	"log"
)

const (
	queen = "Q"
	empty = "."
)

// Board that stores
// our empty spaces and Queens on the table
var Board [][]string

// N contains an integer that
// mean a board of N x N
var N int

//Init just set's the
// nXn value
func Init(num int) {
	N = num
}

// NewBoard an funciont that creates
// a new Board type
func NewBoard() {
	if N > 0 {
		Board = make([][]string, N)
		for i := 0; i < N; i++ {
			Board[i] = make([]string, N)
		}
	} else {
		log.Println("Please init N first")
	}
	// set all members to be dot.
	for i := 0; i < N; i++ {
		for j := 0; j < N; j++ {
			Board[i][j] = empty
		}
	}
}

// PrintBoard just echo's
// our Board
func PrintBoard() {
	var i, j int
	fmt.Printf("\t\t\tQUEEN %d X %d \t\t\t\n\n\n", N, N)
	fmt.Println()
	for i = 0; i < N; i++ {
		for j = 0; j < N; j++ {
			fmt.Printf("\t%s", Board[i][j])
		}
		fmt.Printf("\t\n\n")
	}
	fmt.Println()
}

check.go

package queen

// CheckInstance verifys if
// if we have a quen on a row/col
// if we have a quuen on prime diagonal
// if we have a queen on the second diagonal
func CheckInstance(row, col int) bool {
	// check col
	for i, j := 0, 0; i < N && j < N; i, j = i+1, j+1 {
		if Board[i][col] == queen || Board[row][j] == queen {
			return false
		}
	}

	//prim diagonal
	if row > col {
		startLine := row - col
		for i, j := startLine, 0; i < N && j < N; i, j = i+1, j+1 {
			if Board[i][j] == queen {
				return false
			}
		}
	} else {
		startCol := col - row
		for i, j := 0, startCol; i < N && j < N; i, j = i+1, j+1 {
			if Board[i][j] == queen {
				return false
			}
		}
	}
	// second diagonal
	for i, j := row, col; i < N && j > 0; i, j = i+1, j-1 {
		if Board[i][j] == queen {
			return false
		}
	}

	for i, j := row, col; i > 0 && j < N; i, j = i-1, j+1 {
		if Board[i][j] == queen {
			return false
		}
	}
	return true
}

clear.go

package util

import (
	"fmt"
	"os"
	"os/exec"
	"runtime"
)

// @Global in this pkg
// Declare our own holder type
// to hold all our func definition handlers
// for every clear screen type
// [windows,linux]

var holder map[string]func()

func newMapFunc() {
	holder = make(map[string]func())

	holder["linux"] = func() {
		// At first almost every component is empty
		command := exec.Command("clear")
		// Direct to what screen to point our function
		command.Stdout = os.Stdout
		command.Run()
	}

	holder["windows"] = func() {
		// At first almost every component is empty
		command := exec.Command("cls")
		// Direct the to the coresponding output
		command.Stdout = os.Stdout
		command.Run()
	}
}

// ClearScr a funcion that test if
// our platform is supported and executes
// that specific function
func ClearScr() {
	newMapFunc()
	var osType = runtime.GOOS
	run := holder[osType]
	switch osType {
	case "darwin":
		fmt.Println("Mac os not supported")
		break
	case "linux":
		run()
	case "windows":
		run()
	}

}

main.go

package main

import (
	"fmt"
	"os"
	"strconv"

	"github.com/hoenirvili/Main/queen"
	"github.com/hoenirvili/Main/util"
)

func start() {
	var arg = os.Args
	if len(arg) < 2 {
		panic("Plase enter one argument")
	}
	number, err := strconv.Atoi(arg[1])
	if err != nil {
		panic("Wrong data type, please enter a valid number")
	}
	queen.Init(number)
	queen.NewBoard()
	queen.PrintBoard()
}

func main() {
	util.ClearScr()
	start()

	if queen.BackTrack(0) == true && queen.N > 3 || queen.N == 1 {
		queen.PrintBoard()
	} else {
		fmt.Println("We don't have any")
	}
}