八皇后问题回溯算法

#include <iostream>

#include <stdio.h>

using namespace std;

#include <vector>

using std::vector;

#include <math.h>

#include <cmath>

#define QUEENS 8

int iCount = 0;

int Site[QUEENS];

void Queue(int n);

void Print();

bool isValid(int n);

void Print()

{

    iCount ++ ;

    cout << iCount<<endl;

}

int main(int argc, char *argv[])

{

    Queue(0);

    return 0;

}

void Queue(int n)

{

    if( n == QUEENS )

    {

        Print();

        return ;

    }

    for (int i = 1; i <= QUEENS; ++i)

    {

        Site[n] = i;

        if ( isValid(n) )

        {

            Queue(n+1);

        }

    }

}

bool isValid(int n)

{

    for ( int i = 0 ; i < n; i ++ )

    {

        if ( Site[i] == Site[n] )

        {

            return false;

        }

        if ( abs(Site[i] - Site[n]) == (n-i) )

        {

            return false;

        }

    }

    return true;

}