回旋矩阵算法-Java版本

最新推荐文章于 2024-04-18 15:09:00 发布

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#算法 #面试 #Java #回旋矩阵 #旋转矩阵

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本文介绍了一种用于生成螺旋矩阵的算法实现，该算法能够根据指定的方向（顺时针或逆时针）及起始方向（上、下、左、右）生成特定模式的螺旋矩阵。此外，还提供了Java代码示例，演示如何创建不同大小和旋转方向的矩阵。

之前在面试的时候遇到过这样一个题目：

观察下列数字规律，并将其打印在控制台

3 2 9
4 1 8
5 6 7

13 12 11 10 25
14 03 02 09 24
15 04 01 08 23
16 05 06 07 22
17 18 19 20 21

..........

解题思路：

（1）每个矩阵看成一圈，一圈一圈循环赋值

（2）一圈赋值完成之后，控制向外扩张一圈，就可以实现这个算法了

说明：下面是我加以改进过的算法，实现的任意方向的旋转（顺时针逆时针旋转，上下左右控制初始旋转方向（总共8中构建方法））

package util;

import java.util.regex.Pattern;

public class HuiXuanJuZheng {
	
	
	private int [][] matrix;
	private int x ;
	private int y;
	private String rotateDirection;
	private String direction;
	private String directionInit;
	private int layer;
	/**
	 * 
	 * @param 圈数
	 * @param CCK|CK，逆时针|顺时针
	 * @param up|down|left|right，初次旋转方向 上下左右
	 */
	public HuiXuanJuZheng(int layer,String rotateDirection, String directionInit) {
		if (Pattern.matches("CCK|CK",rotateDirection)&&Pattern.matches("up|down|left|right",directionInit)) {
			this.matrix = new int[2*layer-1][2*layer-1];
			this.x=layer-1;
			this.y=layer-1;
			this.rotateDirection=rotateDirection;
			this.direction=directionInit;
			this.directionInit=directionInit;
			this.layer=layer;
			constructMatrix();
		}else {
			matrix = null;
		}
		
			
		
	}
	
	
	public void constructMatrix(){
		
		/*当前圈数*/
		int currentLayer=1;
		
		/*赋值次数*/
		int time=1;
		String[] flag ={"up","right","down","left"};
		if (rotateDirection == "CCK") {
			String[]flagC = {"down","right","up","left"};
			flag=flagC;
		}
		/*遍历赋值*/
		for (int i = 1; i <= Math.pow(2*layer-1, 2); i++) {
				matrix[x][y] = i;
				boolean fla=false;
				if (Math.pow(2*currentLayer-1,2) == i) {
					currentLayer ++;
					xy(directionInit);
					time=1;
					fla=true;
				}else{
					xy(null);
				}
				time++;
				
				if (rotateDirection == "CCK") {
					switch (direction) {
						case "down":
							if ((2*currentLayer-2) == time) {
								direction = flag[1];
								time=0;
							}
							break;
						case "right":
							if ((2*currentLayer-2) == time) {
								direction = flag[2];
								time=0;
							}
							break;
						case "up":
							if ((2*currentLayer-2) == time) {
								direction = flag[3];
								time=0;
							}
							break;
						case "left":
							if ((2*currentLayer-2) == time) {
								direction = flag[0];
								time=0;
							}
							break;
					}
				}else {
					switch (direction) {
						case "up":
							if ((2*currentLayer-2) == time) {
								direction = flag[1];
								time=0;
							}
							break;
						case "right":
							if ((2*currentLayer-2) == time) {
								direction = flag[2];
								time=0;
							}
							break;
						case "down":
							if ((2*currentLayer-2) == time) {
								direction = flag[3];
								time=0;
							}
							break;
						case "left":
							if ((2*currentLayer-2) == time) {
								direction = flag[0];
								time=0;
							}
							break;
					}
				}
			if (fla) {
				time=1;
				fla=false;
			}
		}
		
		
	}
	
	
	
	



	private void xy(String directionInit) {
		String flay=directionInit!=null?directionInit:direction;
		switch (flay) {
			case "up":
				x--;
				break;
			case "down":
				x++;
				break;
			case "left":
				y--;
				break;
			case "right":
				y++;
				break;
		}
	}

	public int[][] getSwingMatrix(){
		return this.matrix;
		
	}
	
	public static void main(String[] args) {
		
		int [][] mam =new HuiXuanJuZheng(4, "CCK", "up").getSwingMatrix();
		
		for (int[] is : mam) {
			for (int i : is) {
				if (i<100) {
					System.out.print(i<10?"0"+i+"   ":i+"   ");
				}else {
					System.out.print(i+" ");
				}
				
			}
			System.out.println();
		}
		System.out.println();
	}
}