创造一个神奇的广场（Java）

Question

我有点纠结于如何处理这个方阵编码项目。

每当我尝试输入任何值，结果总是为真，方阵是一个幻方。例如,这将是正确的：

16 03 02 13
05 10 11 08
09 06 07 12
04 15 14 01

但当我输入以下值时：

03 04 16 02
05 01 02 10
05 08 07 12
03 14 13 09

这应该返回false，但它仍然返回true，也就是说它是一个幻方。

要求是我需要所有的方法

“public void add（int i,int row,int col）”：在指定位置向矩阵添加一个整数。

公共

“Public boolean AllinRange”：确定矩阵中的所有值是否都在正确的范围内

“Public boolean AllUnique”：确定矩阵中的所有值是否只出现一次

“Public boolean ISMagic”：确定矩阵是否说明幻方。这意味着：

>

用户为某个数字输入了n^2个数字n

这些数字仅介于1和n^2之间（含1和n^2）

每个数字在矩阵中正好出现一次

每一行、每列和两条对角线中元素的和相等

公共类SquareMatrix{

private int[][] array; 


public SquareMatrix(int size) 
{ 
  array = new int[size][size]; 
}


public void add(int i, int row, int column) {array[row][column] = i;} 


//Just checks if the #of rows & columns are between 1-n^2
public boolean allInRange()
{
  int n = array.length;

  for (int row = 0; row < n; row++)
  {
    for (int col = 0; col < array[row].length; col++)
    {
      if (array[row][col] < 1 || array[row][col] > n*n)
        return false; 
    }
  }

  return true;
}

public boolean allUnique()
{
  for (int i =0; i < array.length - 1; i++)
  {
    for (int j = i + 1; j < array.length; j++)
    {
      if(array[i]==array[j])
        return false;
    }
  }
  return true;
}


//Supposed to call the other methods (allInRange & allUnique)
public boolean isMagic()
{

  for(int[] row : array)
  {
    for (int num : row)
    {
      if (num == 0)
        return false;
    }
  }


  boolean range = allInRange();
  if (range == true)
    return true;
  if (range == false)
    return false;

  boolean unique = allUnique();
  if (unique == true)
    return true;
  if (unique == false)
    return false;



  int sumRow;
  int sumCol;
  int sum1 = 0;
  int sum2 = 0;

  //Sum of Left to Right Diaganol
  for (int i = 0; i < array.length; i++)
  {
    sum1 += array[i][i];
  }

  //sum of right to left diaganol
  for (int j = 0; j < array.length; j++)
  {
    sum2 += array[j][array.length-1-j];
  }

  if (sum1 != sum2)
    return false;


  //Sum of Rows
  for (int row = 0; row < array.length; row++)
  {
    sumRow = 0;
    for (int col = 0; col < array[row].length; col++)
      sumRow += array[row][col];

    if (sumRow != sum1)
      return false;
  }


  //Sum of Col
  for (int i = 0; i < array.length; i++)
  {
    sumCol = 0;
    for (int j = 0; j < array.length; j++)
      sumCol = array[j][i];

    if (sumCol != sum1)
      return false;

  }

  return true;    
}



public String toString()
{
  int n = array.length;

  String lol = "";

  for (int[] row : array)
  {
    for (int num : row)
    {
      String hi = String.format("%0"+(n*n+"").length()+"d",num);

      lol += hi + " ";
    }
    lol += "\n";
  }
  return lol;
}

}

这是我的驱动程序类

 import javax.swing.*;


public class SquareMatrixDriver { 
  
  public static void main(String[] args) { //My favorite line in history  
    
    
    JFrame bot = new JFrame(); //We can use JFrame to read the inputs 
    
    do 
    {
      //We have to make sure that it is a valid input or else I am doomed
      int size = 0;
      do 
      {
        size = Integer.parseInt(JOptionPane.showInputDialog(bot, "Enter the size of the matrix."));
        if (size < 1) 
        {
          JOptionPane.showMessageDialog(bot, "Invalid size! Enter a number greater than 0.");
        }
      } 
      while(size < 1);
      
      SquareMatrix matrix = new SquareMatrix(size);
      
      for (int i=0; i<size; i++) 
      {
        //Gets thhe User's Input
        
        String[] stringInput;
        do 
        {
          stringInput = JOptionPane.showInputDialog(bot, "Enter the row number" + (i + 1) + ", with " + size + " elements, split by commas.").split(",");
          if (stringInput.length != size) 
          { //In this code we basically enter the numbers with commas
            JOptionPane.showMessageDialog(bot, "Invalid size! " + stringInput.length + " elements entered but " + size + " required.");
          }
        } 
        while(stringInput.length != size);
        
        int[] intInput = new int[size];
        for (int o=0; o<size; o++) 
        { 
          
        }
        
        for (int o=0; o<size; o++) 
        {
          matrix.add(Integer.parseInt(stringInput[o]), i, o); //Here we would put everything into the Matrix
        }
      }
      
      
      JOptionPane.showMessageDialog(bot, "The matrix is " + (matrix.isMagic()? "very" : "not") + " correct"); //This line will output if the Matrix works or doesnt work 
      
      JOptionPane.showMessageDialog(bot, matrix); // Enters out the final output
    } while (JOptionPane.showConfirmDialog(bot, "Do you wish to exit?", "Exit", JOptionPane.YES_NO_OPTION) == 1); //Asks the User if they would like to exit the program
  }
}






      
      
     

Answer 1

我可以通过目测发现的错误：

allUnique（）是完全错误的，您必须检查每个数字在矩阵中是否只出现一次，但您比较的是完全不同的行数组，检查唯一性的最佳方法通常是使用哈希集，但由于这里有一个非常定义的数字范围（从1到n²)，所以使用n²布尔数组。扫描方阵并测试/设置数组中的相应元素，如果已经设置，则返回false。

public boolean allUnique() {
  int n=array.length;
  boolean[] set=new boolean[n*n];
  for (int i=0; i < n; i++) {
    for (int j=0;j < n; j++) {
      //Here assuming that you already sucessfully called allInRange, 
      //otherwise we must check bounds to avoid an index out of bounds exception
      if(set[array[i][j]-1]) {
        return false;
      }
      set[array[i][j]-1] = true;
    }
  }
  return true;
}

在方法isMagic（）中，所有这部分都是错误的和多余的

 boolean range = allInRange();
  if (range == true)
    return true;  //WRONG, this will immediately return with true, without further checks
  if (range == false)
    return false;

  boolean unique = allUnique();
  if (unique == true)
    return true;  //WRONG, same as before
  if (unique == false)
    return false;

只需将其替换为

if (!allInRange()) {
    return false;
}
if (!allUnique()) {
    return false;
}

最后，在isMagic（）中，当计算列的和时，缺少加法

sumCol = array[j][i];

必须替换为

sumCol += array[j][i];