关于8皇后以及N皇后算法探究,自己写的网格算法,递归方案。记录下

package com.xmh.test;

public class Queen {
	/**
	 * 棋盘大小
	 */
	private static int Checkerboard_size = 8;
	
	/**
	 * 皇后 棋格
	 */
	private static QueenVo QUEEN_VO = new QueenVo(0, 0, Checkerboard_size);

	/**
	 * 统计
	 */
	private static int count = 0;

	public static void main(String[] args) {
		for (int i = 8; i < 16; i++) {
			long stratTime = System.currentTimeMillis();
			
			Checkerboard_size = i;
			
			QUEEN_VO = new QueenVo(0, 0, Checkerboard_size);
			/*
			 * 初始化
			 */
			init();

			putQueenAtRow(0);

			long endTime = System.currentTimeMillis();

			System.out.println(i + "皇后用时 : " + (endTime - stratTime) + " 结果 " + count);

			count = 0;
		}
	}

	private static void print(QueenVo queenVo) {
		for (int i = 0; i < Checkerboard_size; i++) {
			for (int j = 0; j < Checkerboard_size; j++) {
				QueenVo vo = find(queenVo, i, j);
				System.out.print(vo.isQueen() ? "1 " : "0 ");
			}
			System.out.println();
		}
	}

	/**
	 * 利用递归和循环算出来到底有几种解
	 * 
	 * @param row
	 */
	private static void putQueenAtRow(int row) {
		QueenVo cache = QUEEN_VO;

		if (row == Checkerboard_size) {
			count++;
//			System.out.println("第" + count + "次解 \n");
//			print(QUEEN_VO);
			return;
		}
		for (int i = 0; i < row; i++) {
			cache = cache.getDown();
		}

		while (true) {
			if (cache == null) {
				break;
			}
			if (isSafety(cache)) {
				cache.setQueen(true);
				putQueenAtRow(row + 1);
				cache.setQueen(false);
			}
			cache = cache.getRight();
		}
	}

	/**
	 * 检验是否安全
	 * 
	 * @param QUEEN
	 * @return
	 */
	private static boolean isSafety(QueenVo QUEEN) {
		QueenVo cache = QUEEN;
		if (QUEEN == null) {
			return false;
		}
		while (true) {
			cache = cache.getUp();
			if (cache == null) {
				break;
			} else if (cache.isQueen()) {
				return false;
			}
		}

		cache = QUEEN;

		while (true) {
			if (cache.getUp() == null) {
				break;
			}

			cache = cache.getUp().getLeft();

			if (cache == null) {
				break;
			}
			if (cache.isQueen()) {
				return false;
			}
		}

		cache = QUEEN;

		while (true) {
			if (cache.getUp() == null) {
				break;
			}

			cache = cache.getUp().getRight();

			if (cache == null) {
				break;
			}
			if (cache.isQueen()) {
				return false;
			}
		}

		return true;
	}

	/**
	 * 根据棋盘中的任意一个棋格找到复合下标的queenvo
	 * 
	 * @param QUEEN
	 * @param line
	 * @param column
	 * @return
	 */
	private static QueenVo find(QueenVo QUEEN, int line, int column) {
		QueenVo vo = directionFor(QUEEN, true, true, line, column);
		if (vo == null) {
			vo = directionFor(QUEEN.getLeft(), false, false, line, column);
		}
		return vo;
	}

	private static QueenVo directionFor(QueenVo queenVo, boolean isRigth, boolean isDown, int line, int column) {
		if (queenVo == null) {
			return null;
		}
		if (queenVo.getColumn() == column && queenVo.getLine() == line) {
			return queenVo;
		}

		if (isRigth) {
			if (queenVo.getRight() != null) {
				return directionFor(queenVo.getRight(), isRigth, isDown, line, column);
			} else {
				if (isDown) {
					return directionFor(queenVo.getDown(), !isRigth, isDown, line, column);
				} else {
					return directionFor(queenVo.getUp(), !isRigth, isDown, line, column);
				}
			}
		} else {
			if (queenVo.getLeft() != null) {
				return directionFor(queenVo.getLeft(), isRigth, isDown, line, column);
			} else {
				if (isDown) {
					return directionFor(queenVo.getDown(), !isRigth, isDown, line, column);
				} else {
					return directionFor(queenVo.getUp(), !isRigth, isDown, line, column);

				}
			}
		}
	}

	public static int getCheckerboardSize() {
		return Checkerboard_size;
	}

	private static void init() {
		QUEEN_VO.setRight(new QueenVo(0, 1, Checkerboard_size));

		QueenVo rightCache = QUEEN_VO.getRight();

		QUEEN_VO.setDown(new QueenVo(1, 0, Checkerboard_size));

		QueenVo downCache = QUEEN_VO.getDown();

		for (int i = 0; i < Checkerboard_size; i++) {
			if (i != 0) {
				downCache.setRight(new QueenVo(i, 1, Checkerboard_size));

				rightCache = downCache.getRight();

				rightCache.setUp(rightCache.getLeft().getUp().getRight());

				if (i != Checkerboard_size - 1) {
					downCache.setDown(new QueenVo(i + 1, 0, Checkerboard_size));

					downCache = downCache.getDown();
				}
			}
			for (int j = 2; j < Checkerboard_size; j++) {
				rightCache.setRight(new QueenVo(i, j, Checkerboard_size));
				if (i != 0) {
					rightCache.getRight().setUp(rightCache.getUp().getRight());
				}
				rightCache = rightCache.getRight();
			}
		}
	}

//	public static boolean isOdd(int i) {
//		return (i & 1) == 1;
//	}

}

class QueenVo {

	private int line = 0;

	private int column = 0;

	private QueenVo up = null;
	private QueenVo down = null;
	private QueenVo left = null;
	private QueenVo right = null;

	private boolean isQueen = false;

	public QueenVo(int line, int column, int size) {
		if (line < 0 || column < 0 || line > size - 1
				|| column > size - 1) {
			throw new RuntimeException("行和列不能小于0!  并且不能大于7");
		}
		this.line = line;
		this.column = column;
	}

	public int getLine() {
		return line;
	}

	public void setLine(int line) {
		this.line = line;
	}

	public int getColumn() {
		return column;
	}

	public void setColumn(int column) {
		this.column = column;
	}

	public QueenVo getUp() {
		return up;
	}

	public void setUp(QueenVo up) {
		this.up = up;
		if (up.getDown() != this) {
			up.setDown(this);
		}
	}

	public QueenVo getDown() {
		return down;
	}

	public void setDown(QueenVo down) {
		this.down = down;
		if (down.getUp() != this) {
			down.setUp(this);
		}
	}

	public QueenVo getLeft() {
		return left;
	}

	public void setLeft(QueenVo left) {
		this.left = left;
		if (left.getRight() != this) {
			left.setRight(this);
		}
	}

	public QueenVo getRight() {
		return right;
	}

	public void setRight(QueenVo right) {
		this.right = right;
		if (right.getLeft() != this) {
			right.setLeft(this);
		}
	}

	public boolean isQueen() {
		return isQueen;
	}

	public void setQueen(boolean isQueen) {
		this.isQueen = isQueen;
	}

}

 

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