8queen.go

package main

import ("fmt"
//  "math"
 )
const max =8

func main(){
        q := Queen{sum:0}
        q.put(0)
        fmt.Println(q.sum)
        return
}



type Queen struct{
        desk [max]int
        sum int
}
func (this *Queen)show(){
        for i:=0;i<max ;i++{
                fmt.Print("(",i,",",this.desk[i],")")
        }
        fmt.Println("\n")
        this.sum++
}
func (this *Queen)check(n int)bool{
        for i:=0;i<n ;i++{
                if this.kill(i,n){
                        return false
                }
        }
        return true;
}
func abs(l int)int{
        if l>= 0 {
                return l
        }else{
                return -l
        }
}
func (this *Queen)kill(i int,n int) bool{
        return this.desk[i] == this.desk[n] || abs(this.desk[i]-this.desk[n]) == (n-i )
}
func (this *Queen)put(n int){
        // fmt.Println(max)
        for i:=0;i<max ;i++{
                this.desk[n] = i ;
                if  this.check(n){
                        if n == max -1 {
                                this.show()
                        }else{
                                this.put(n+1)
                        }
                }
        }
}