以反螺旋形式打印矩阵的Java程序

给定一个二维数组，任务是以反螺旋形式打印矩阵：
例子：

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

Input : arr[][4] = {1, 2, 3, 4
                    5, 6, 7, 8
                    9, 10, 11, 12
                    13, 14, 15, 16};
Output : 10 11 7 6 5 9 13 14 15 16 12 8 4 3 2 1

Input :arr[][6] = {1, 2, 3, 4, 5, 6
                  7, 8, 9, 10, 11, 12
                  13, 14, 15, 16, 17, 18};
Output : 11 10 9 8 7 13 14 15 16 17 18 12 6 5 4 3 2 1

这个想法很简单，我们以螺旋形式遍历矩阵并将所有遍历的元素放入堆栈中。最后从堆栈中逐一打印并打印它们。

Java

// Java Code for Print matrix in antispiral form
import java.util.*;
  
class GFG {
      
    public static void antiSpiralTraversal(int m, int n, 
                                             int a[][])
    {
        int i, k = 0, l = 0;
       
        /*  k - starting row index
            m - ending row index
            l - starting column index
            n - ending column index
            i - iterator  */
        Stack stk=new Stack();
       
        while (k <= m && l <= n)
        {
            /* Print the first row from the remaining 
             rows */
            for (i = l; i <= n; ++i)
                stk.push(a[k][i]);
            k++;
       
            /* Print the last column from the remaining
            columns */
            for (i = k; i <= m; ++i)
                stk.push(a[i][n]);
            n--;
       
            /* Print the last row from the remaining 
            rows */
            if ( k <= m)
            {
                for (i = n; i >= l; --i)
                    stk.push(a[m][i]);
                m--;
            }
       
            /* Print the first column from the remaining 
            columns */
            if (l <= n)
            {
                for (i = m; i >= k; --i)
                    stk.push(a[i][l]);
                l++;
            }
        }
       
        while (!stk.empty())
        {
            System.out.print(stk.peek() + " ");
            stk.pop();
        }
    }
      
    /* Driver program to test above function */
    public static void main(String[] args) 
    {
         int mat[][] =
                {
                    {1,  2,  3,  4,  5},
                    {6,  7,  8,  9,  10},
                    {11, 12, 13, 14, 15},
                    {16, 17, 18, 19, 20}
                };
               
        antiSpiralTraversal(mat.length - 1, mat[0].length - 1, 
                                                       mat);
    }
  }
// This code is contributed by Arnav Kr. Mandal.

输出：

12 13 14 9 8 7 6 11 16 17 18 19 20 15 10 5 4 3 2 1 

有关详细信息，请参阅以反螺旋形式打印矩阵的完整文章！