Code:
#include iostream
#include cstdio
#include cstdlib
#define N 8
using namespace std;
/* print solution */
void printSolution(int board[N][N])
{
for (int i = 0; i < N; i++)
{
for (int j = 0; j < N; j++)
cout<
cout<
}
}
/* check if a queen can be placed on board[row][col]*/
bool isSafe(int board[N][N], int row, int col)
{
int i, j;
for (i = 0; i < col; i++)
{
if (board[row][i])
return false;
}
for (i = row, j = col; i >= 0 && j >= 0; i--, j--)
{
if (board[i][j])
return false;
}
for (i = row, j = col; j >= 0 && i < N; i++, j--)
{
if (board[i][j])
return false;
}
return true;
}
/*solve N Queen problem */
bool solveNQUtil(int board[N][N], int col)
{
if (col >= N)
return true;
for (int i = 0; i < N; i++)
{
if ( isSafe(board, i, col) )
{
board[i][col] = 1;
if (solveNQUtil(board, col + 1) == true)
return true;
board[i][col] = 0;
}
}
return false;
}
/* solves the N Queen problem using Backtracking.*/
bool solveNQ()
{
int board[N][N] = {0};
if (solveNQUtil(board, 0) == false)
{
cout<<"Solution does not exist"<
return false;
}
printSolution(board);
return true;
}
// Main
int main()
{
solveNQ();
return 0;
}
Output:
1 0 0 0 0 0 0 0
0 0 0 0 0 0 1 0
0 0 0 0 1 0 0 0
0 0 0 0 0 0 0 1
0 1 0 0 0 0 0 0
0 0 0 1 0 0 0 0
0 0 0 0 0 1 0 0
0 0 1 0 0 0 0 0
------------------
(program exited with code: 1)
Press return to continue
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