【IT面试题005】八皇后

/*
 8皇后
*/

#include "stdafx.h"

#include <iostream>
#include <string>
#include <vector>
using namespace std;


const int MAX_ELEMENT = 1000;
int solution[MAX_ELEMENT];
bool columnHasChess[MAX_ELEMENT];
bool addDialogHasChess[MAX_ELEMENT];  
bool subDialogHasChess[MAX_ELEMENT];

int gN; //行数
int gSolCount;
void PrintSolution()
{
	for (int i = 0;i < gN;i++)
	{
		cout << solution[i] << " ";
	}
	cout << endl;
}
//check 皇后是否能放在[row,col]
bool check(int row,int col)
{
	if (columnHasChess[col])
	{
		return false;
	}
	if (addDialogHasChess[row + col])
	{
		return false;
	}
	if (subDialogHasChess[row - col + gN])
	{
		return false;
	}
	return true;
}
void Go(int row)
{
	if (row == gN)
	{
		gSolCount ++;
		PrintSolution();
		return;
	}
	//第row行选择那一列呢
	for (int i = 0;i < gN;i++)
	{
		if (check(row,i))
		{
			columnHasChess[i] = true;
			addDialogHasChess[i + row] = true;
			subDialogHasChess[row - i + gN] = true;
			solution[row] = i;
			Go(row + 1);
			columnHasChess[i] = false;
			addDialogHasChess[i + row] = false;
			subDialogHasChess[row - i + gN] = false;
		}
	}
}
int _tmain(int argc, _TCHAR* argv[])
{

	gN = 8;
	gSolCount = 0;
	memset(columnHasChess,0,sizeof(columnHasChess));
	memset(addDialogHasChess,0,sizeof(addDialogHasChess));
	memset(subDialogHasChess,0,sizeof(subDialogHasChess));
	Go(0);
	cout << gSolCount << endl;
}