8 quân hậu.

// Xay dung code bai toan 8 quan hau
// Khai bao cac ham thu vien neu co
#include <iomanip>
#include <iostream>
#include <malloc.h>
#include <memory.h>
using namespace std;
//
int j;
#define RANK 8
//kiem tra quan hau
void queens_checker(int** queens, int rank, int current)
{
	int order = 0;
	int i, j;
	int s1 = 0, s2 = 0, s3 = 0, s4 = 0; int k;
	if (current == rank)
	{
		cout << " Cach " << ++order << endl << endl;
		for (i = 0; i < rank; i++)
		{
			for (j = 0; j < rank; j++)
			cout << setw(3) << queens[i][j];
			cout << endl << endl;
		}
		cout << endl;
		return;
	}
	for (j = 0; j < rank; j++)
	{
		s1 = 0; s2 = 0; s3 = 0; s4 = 0;
		if (!queens[current][j])
		{
			queens[current][j] = 1;
		for (i = 0; i < rank; i++) //tính t?ng c?t hàng
		{
			s1 += queens[current][i];
			s2 += queens[i][j];
		} k = 1;
		s3 = queens[current][j];
	while ((current + k) < rank && (j + k) < rank)
	{
		s3 += queens[current + k][j + k];
		++k;
	} k = -1;
	while ((current + k) >= 0 && (j + k) >= 0)
	{
		s3 += queens[current + k][j + k];
		--k;
	} k = 1;
	s4 = queens[current][j];
	while ((current + k) < rank && (j - k) >= 0)
	{
	s4 += queens[current + k][j - k];
	++k;
	} k = -1;
	while ((current + k) >= 0 && (j - k) < rank)
	{
	s4 += queens[current + k][j - k];
	--k;
	}
	if ((s1 < 2) && (s2 < 2) && (s3 < 2) && (s4 < 2)) // tinh chat co vua
		queens_checker(queens, rank, current + 1);
	queens[current][j] = 0;
		}
	}
}
// chuong trinh chinh
int main()
{
	int** queens; int i; int rank = RANK;
	queens = (int **)malloc(rank * sizeof(int *));
	for (i = 0; i < rank; i++)
	{
		queens[i] = (int *)malloc(rank * sizeof(int));
		memset(queens[i], 0, rank * sizeof(int));
	}
	queens_checker(queens, rank, 0);
	for (i = 0; i < rank; i++)

		free(queens[i]);
		free(queens);

	return 0;
}
// Nhan Ctrl + F7 de bien dich chuong trinh
// Nhan Ctrl + F5 de chay chuong trinh
// Chung ta se co 12 cach de giai bai toan