回溯法：n皇后有关问题

回溯法：n皇后问题

 

 

 

/**
 * n-皇后问题
 */
package com.iteye.caoruntao.nqueen;

/**
 * @author caoruntao
 *
 */
public class NQueen {

	private int x[];
	private int n;
	
	public NQueen(int n){
		this.n = n;
		this.x = new int[n];
	}
	
	public boolean place(int k){
		int i = 0;
		while(i < k){
			if((x[i] == x[k]) || (Math.abs(x[i]-x[k]) == Math.abs(i-k))){
				return false;
			}
			i++;
		}
		return true;
	}
	
	public void printResult(){
		for(int i=0; i<x.length; i++){
			System.out.println(x[i]+" ");
		}
	}
	
	public void ComputerNQueen(){
		int k = 0;
		this.x[0] = 0;
		while(k >= 0){
			x[k] = x[k]+1;
			while(x[k] <= n && !place(k)){
				x[k] = x[k]+1;
			}
			if(x[k] <= n){
				if(k == n-1){
					printResult();
					System.out.println("************");
					x[k] = x[k]+1;
					//return;
				}
				else{
					k = k+1;
					x[k] = 0;
				}
			}
			else{
				k = k-1;
			}
		}
	}
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		NQueen nQueen = new NQueen(4);
		nQueen.ComputerNQueen();
	}

}