如何在 Java 中查找矩阵中已排序的行数？

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矩阵不过是一组以二维矩形布局排列的数据元素的集合。在 Java 中，二维数组可以被视为矩阵。

根据问题陈述，任务是计算矩阵中所有以严格递增顺序或严格递减顺序排序的行。

让我们深入研究本文，了解如何使用 Java 编程语言来实现它。

举几个例子

示例 1

Suppose the original matrix is{ 
   { 5, 6, 7, 8 ,
   { 5, 3, 1, 0 },
   { 10, 7, 4, 3 },
   { 13, 7, 8, 21 },
   { 5, 4, 11 ,22 },
   { 11, 2, 3 ,4 }
};

在计算矩阵中已排序的行后，结果索引将是

矩阵中已排序的行：3

示例 2

Suppose the original matrix is{
   { 3, 5, 7, 9 },
   { 5, 3, 1, 8 },
   { 10, 7, 4, 3 },
   { 4, 7, 8, 11 },
   { 0, 4, 11 ,22 },
   { 1, 2, 3 ,0 }
};

在计算矩阵中已排序的行后，结果索引将是

矩阵中已排序的行：4

算法

步骤 1 - 初始化并声明矩阵

步骤 2 - 使用 for 循环检查行的递增或递减顺序。

步骤 3 - 统计行总数。

步骤 4 - 打印结果。

多种方法

我们提供了不同方法的解决方案

• 使用矩阵的静态初始化

• 使用用户定义的方法

让我们逐一查看程序及其输出。

方法 1：使用矩阵的静态初始化

在这种方法中，矩阵元素将在程序中初始化。然后根据算法，查找矩阵中已排序的行数。

示例

public class Main {
   public static void main(String arg[]){
      int m = 6, n = 4; //Initialising and declaring the matrix
      int mat[][] = {
         { 5, 6, 7, 8 },
         { 5, 3, 1, 0 },
         { 10, 7, 4, 3 },
         { 13, 7, 8, 21 },
         { 5, 4, 11 ,22 },
         { 11, 2, 3 ,4 }
      };
      int result = 0; 
      
      // counting from left to right side to count increasing order of rows
      for (int i = 0; i < m; i++) {
        
        //To check if there is any pair of element that are not in increasing order.
         int j;
         for (j = 0; j < n - 1; j++)
         if (mat[i][j + 1] <= mat[i][j])
         break;
         
         //If the loop didn't break then all elements of current row were in increasing order
         if (j == n - 1)
        
        //count of increasing order
         result++;
      }
      
      // counting from right to left side to count decreasing order of rows
      for (int i = 0; i < m; i++) {
         
         //To check if there is any pair of elements that are not in decreasing order.
         int j;
         for (j = n - 1; j > 0; j--)
         if (mat[i][j - 1] <= mat[i][j])
            break;
         if (n > 1 && j == 0)
            result++;
      }
      System.out.println("The sorted rows in a matrix: " + result);
   }
}

输出

The sorted rows in a matrix: 3

方法 2：使用用户定义的方法

在这种方法中，矩阵元素将在程序中初始化。然后通过将矩阵作为参数传递来调用用户定义的方法，并在方法内部根据算法查找矩阵中已排序的行数。

示例

public class Main {
   public static void main(String arg[]){
      
      //Initialising and declaring the matrix
      int m = 6, n = 4;
      int mat[][] = {
         { 3, 5, 7, 9 },
         { 5, 3, 1, 8 },
         { 10, 7, 4, 3 },
         { 4, 7, 8, 11 },
         { 0, 4, 11 ,22 },
         { 1, 2, 3 ,0 }
      };
      
      //calling user defined method
      sort(mat, m, n);
   }
   
   // user defined method
   static void sort(int mat[][], int r, int c){
      
      //Initializing the result
      int result = 0; 
     
     // counting from left to right side to count increasing order of rows
      for (int i = 0; i < r; i++) {
         
         //To check if there are any pairs of elements that are not in increasing order.
         int j;
         for (j = 0; j < c - 1; j++)
         if (mat[i][j + 1] <= mat[i][j])
         break;
         
         //If the loop didn't break then all elements of current row were in increasing order
         if (j == c - 1)
         
         //count of increasing order
         result++;
      }
      
      // counting from right to left side to count decreasing order of rows
      for (int i = 0; i < r; i++) {
        
        //To check if there is any pair of elements that are not in decreasing order.
         int j;
         for (j = c - 1; j > 0; j--)
         if (mat[i][j - 1] <= mat[i][j])
            break;
        
        //If the loop didn't break then all elements of current row were in decreasing order
         if (c > 1 && j == 0)
        
        //count of decreasing order
            result++;
      }
      
      //print the result
      System.out.println("The sorted rows in a matrix: " + result);
   }
}

输出

The sorted rows in a matrix: 4

在本文中，我们探索了使用 Java 编程语言查找矩阵中已排序的行数的不同方法。