Question

因此，正如标题所述，我正在尝试将一个程序组合在一起，该程序将比较二维数组的行并确定是否有相同的行。

这必须分两个部分完成；确定是否有任何行是相同的，并确定有多少行是相同的。我正在尝试使用布尔方法确定是否存在任何相同的行，并且尝试使用单独的方法来确定如果布尔方法返回true则有多少行相同。

例如，如果数组为：

1 2 3
2 3 1
1 2 3

然后，布尔方法将返回true，并且输出为：

The matrix has 2 identical rows.

问题是我不知道如何设置布尔方法；如果我能弄清楚那么多，程序的其余部分将很容易弄清楚。

如何为此设置布尔方法？

如果有人需要，这是我到目前为止提出的代码：

public class IdenticalRows {

    public static void main(String[] args) {
        Scanner KBin = new Scanner(System.in);
        char run;
        int ROW, COL;

        System.out.println("Would you like to begin? (Y/N)");
        run = KBin.next().charAt(0);
        do {
            if(run!='y' && run!='Y' && run!='n' && run!='N') {
                System.out.println("Please only type 'y' or 'Y' to begin or type 'n' or 'N' to close the program.");
                System.out.println("Would you like to begin? (Y/N)");
                run = KBin.next().charAt(0);
            }
        }while(run!='y' && run!='Y' && run!='n' && run!='N');

        do {
            System.out.println("Please enter the number of rows:");
            ROW = KBin.nextInt();
            do {
                if (ROW<=0) {
                    System.out.println("Entry invalid; must be a positive integer greater than 0.");
                    System.out.println("Please enter the number of rows:");
                    ROW = KBin.nextInt();
                }   
            }while(ROW<=0);
            System.out.println("Please enter the number of columns:");
            COL = KBin.nextInt();
            do {
                if (COL<=0) {
                    System.out.println("Entry invalid; must be a positive integer greater than 0.");
                    System.out.println("Please enter the number of columns:");
                    COL = KBin.nextInt();
                }   
            }while(COL<=0);

            int[][] testDuplicates = new int[ROW][COL];
                randArray (testDuplicates, MIN, MAX);
            System.out.println("Thematrix is:");
                printArray(testDuplicates);
                    System.out.println(" ");
            boolean presence = duplicates(testDuplicates);
                if (presence=true) {
                    countDuplicates(testDuplicates);
                }
                else if (presence=false) {
                    System.out.println("There are no identical rows in this matrix.");
                }
            System.out.println("Would you like to run the program again? (Y/N)");
            run = KBin.next().charAt(0);
        }while(run=='y' || run=='Y');
    }

    public static void randArray(int[][] matrix, int low, int up) {//Establishes the values of the elements of the array
        Random rand = new Random();
        for (int r = 0; r < matrix.length; r++) {
            for (int c = 0; c < matrix[r].length; c++) {
                matrix[r][c] = rand.nextInt(up-low+1)+low;
            }   
        }   
    }

    public static void printArray(int[][] matrix) {//Prints the elements of the array in a square matrix
        for (int r = 0; r < matrix.length; r++) {
            for (int c = 0; c < matrix[r].length; c++) {
                System.out.printf("%5d",matrix[r][c]);
            }
            System.out.println(" ");
        }
    }

    public static boolean duplicates(int[][] list) {//Determines if any row(s) of elements ever repeat
         for (int r=0; r<list.length; r++) {
             for (int c=0; c<list[r].length; c++) {

             }
         } 
         return false;
    }

    public static void countDuplicates(int[][] matrix) {
        for (int r=0; r<matrix.length; r++) {
            for (int c=0; c<matrix[r].length; c++) {

            }
        }
    }

    public static final int MAX=3;
    public static final int MIN=1;
}

在此先感谢您能提供帮助的人！

Answer 1

首先编写比较两行的方法：

private static boolean areIdentical(int[] a1, int[] a2) {
    if(a1.length != a2.length) return false;
    for(int i = 0; i < a1.length; i++) {
        if(a1[i] != a2[i]) return false; 
    }
    return true;
}

现在，您可以使用此方法比较行。只需从数组中获取每一行，然后将其与下面的每一行进行比较。类似于下一个：

public static boolean duplicates(int[][] list) {
    for (int j = 0; j < list.length; j++) {
         if(j == list.length-1) return false; //don't need to compare last row
         for (int i = j + 1; i < list.length; i++) {
             if(areIdentical(list[j], list[i])) return true;
         }
     } 
     return false;
}

您可以轻松地修改此代码以计算重复次数。

Java程序来确定二维数组的矩阵中是否有重复的行？

1 个答案: