算法题-循环打印矩阵

要求：给定一个二维数组，按边依次循环打印数组元素。

示例一：
1  2  3  4
5  6  7  8
9  10 11 12
13 14 15 16

输出：1 2 3 4 8 12 16 15 14 13 9 5 6 7 11 10

示例二：
1  2  3  4 
5  6  7  8 
9 10 11 12

输出：1 2 3 4 8 12 11 10 9 5 6 7

示例三：
1  2  3  
4  5  6  
7  8  9 
10 11 12

输出：1 2 3 6 9 12 11 10 7 4 5 8

代码：

public static void main(String[] args) {
          
   

	int[][] arr = new int[][]{
          
   {
          
   1,2,3,4}, {
          
   5,6,7,8}, {
          
   9,10,11,12},{
          
   13,14,15,16}};
	String res = traverse(arr);
	System.out.println(res);

    int[][] a = new int[][]{
          
   {
          
   1,2,3,4}, {
          
   5,6,7,8}, {
          
   9,10,11,12}};
    String ares = traverse(a);
    System.out.println(ares);

    int[][] b = new int[][]{
          
   {
          
   1,2,3}, {
          
   4,5,6}, {
          
   7,8,9}, {
          
   10,11,12}};
    String bres = traverse(b);
    System.out.println(bres);
}


public static String traverse(int[][] arr) {
          
   
    int row = arr.length;
    int cloum = arr[0].length;

    StringBuffer buffer = new StringBuffer();

    for (int s = 0; s < Math.min((row+1)/2,(cloum+1)/2); s++) {
          
   
        int x0 = s;
        int x1 = row-s;
        int y0 = s;
        int y1 = cloum-s;

        for (int i = x0; i < y1 ; i++) {
          
   
            buffer.append(arr[x0][i]+" ");
        }

        if(row-2*s==1){
          
   
            continue;
        }

        for (int i = y0+1; i < x1; i++) {
          
   
            buffer.append(arr[i][y1-1]+" ");
        }

        if(cloum-2*s==1){
          
   
            continue;
        }

        for (int i = y1-2; i >= x0; i--) {
          
   
            buffer.append(arr[x1-1][i]+" ");
        }

        for (int i = x1-2; i >= y0+1; i--) {
          
   
            buffer.append(arr[i][y0]+" ");
        }
    }
    return buffer.toString().trim();
}