NQueens - My solution

N queens Solution.java

package com.demo.advjava;

public class NQueensTesting {

	int boardSize = 8;
	int[][] board = new int[boardSize][boardSize];

	public void populateBoard() {
		int i, j;
		for (i = 0; i < boardSize; i++)
			for (j = 0; j < boardSize; j++)
				board[i][j] = 0;
	}

	public void printBoard() {
		int i, j;
		for (i = 0; i < boardSize; i++) {
			for (j = 0; j < boardSize; j++)
				System.out.print(board[i][j] + " ");
			System.out.println();
		}
	}

	public boolean placeQueen(int col) {
		int i;
		if (col >= boardSize)
			return true;
		for (i = 0; i < boardSize; i++) {
			if (isSafe(i, col)) {
				board[i][col] = 1;
				if (placeQueen(col + 1))
					return true;
				board[i][col] = 0;
			}

		}
		return false;
	}

	private boolean isSafe(int row, int col) {
		int i, j;
		for (i = 0; i < col; i++)
			if (board[row][i] == 1)
				return false;

		for (i = row, j = col; i >= 0 && j >= 0; i--, j--)
			if (board[i][j] == 1)
				return false;

		for (i = row, j = col; j >= 0 && i < board.length; i++, j--)
			if (board[i][j] == 1)
				return false;

		return true;
	}

	public static void main(String[] args) {
		NQueensTesting nt = new NQueensTesting();
		nt.populateBoard();
		nt.placeQueen(0);
		nt.printBoard();
	}
}