從數獨矩陣的每一行和列中移除一個隨機元素

Question

在之前的文章中，我提到了如何從每行中移除一個數獨矩陣中的一個元素。現在，我正在想辦法從Sudoku矩陣中移除一個元素，但對於每一行和一列。我正在考慮創建一個數組，該數組存儲列索引從元素被刪除的行中。然後在下一行中，您迭代刪除另一個元素檢查以查看您刪除的數字是否存儲在先前存儲的列索引中。雖然我不認爲這將是一個非常有效的算法。從行方法

移除元件

public static void remove_Sud (int [][] S){ // Remove sudoku method 
    for(int i = 0; i < S.length; i++){ // For loop iterate through length of matrix array 
     int randomPosition = (int) Math.floor(Math.random() * S.length); //Random number between 0 and 2 
     S[i][randomPosition] = 0; // 0 or whatever you use to represent blank 
    } 

} 

Sudoku Matrix

Answer 1

爲了有效地做到這一點，我建議創建索引的兩個陣列（一個用於列，一個用於排），每9 INT長。這比使用列表更有效率。然後，我們用0-8不重複整數的置換填充它們，並把它們作爲一個地圖，其在基體元件以輸入0

這裏的一個示例代碼：

public static void removeSudoku(int[][] sudoku) { 
    Random rand = new Random(); 
    int[] cols = {-1,-1,-1,-1,-1,-1,-1,-1,-1}; 
    int[] rows = {-1,-1,-1,-1,-1,-1,-1,-1,-1}; 

    //We need to choose an index for each number 0-8 inclusive. 
    for (int i=0;i<9;i++) { 

     //get a random index on the column array for i 
     int randomInt = rand.nextInt(9); 
     //In case this random index is already populated - 
     //rand again until an empty spot is available. 
     while (cols[randomInt]!=-1) { 
     randomInt = rand.nextInt(9); 
     } 
     cols[randomInt] = i; 

     //Same thing for the rows - get a random index in the 
     //array for i, rand again if needed. 
     randomInt = rand.nextInt(9); 
     while (rows[randomInt]!=-1) { 
     randomInt = rand.nextInt(9); 
     } 
     rows[randomInt] = i; 
    } 

    //Now that we have the two arrays filled in with a random 
    //permutation of ints 0-8, we can use it to remove the 
    //elements from the sudoku. 
    for (int i=0;i<9;i++) { 
     sudoku[rows[i]][cols[i]] = 0; 
    } 
    } 

    //Just for printout 
    public static void printSoduku(int[][] sudoku) { 
    for (int i=0;i<9;i++) { 
     for(int j=0;j<9;j++) { 
     System.out.print(sudoku[i][j]+" "); 
     if (j==2 || j==5) { 
      System.out.print("|"); 
     } 
     } 
     System.out.println(); 
     if (i==2 || i==5) { 
     System.out.println("-------------------"); 
     } 
    } 
    } 

    public static void main(String[] args) throws IOException { 

    int[][] soduku = new int[][] {{1,2,3,4,5,6,7,8,9}, 
    {4,5,6,7,8,9,1,2,3},{7,8,9,1,2,3,4,5,6}, 
    {2,3,4,5,6,7,8,9,1},{5,6,7,8,9,1,2,3,4}, 
    {8,9,1,2,3,4,5,6,7},{3,4,5,6,7,8,9,1,2}, 
    {6,7,8,9,1,2,3,4,5},{9,1,2,3,4,5,6,7,8}}; 
    printSudoku(sudoku); 
    removeSudoku(sudoku); 
    System.out.println(); 
    printSudoku (sudoku); 
    } 

輸出將原始數獨矩陣，然後刪除一個：

1 2 3 |4 5 6 |7 8 9 
4 5 6 |7 8 9 |1 2 3 
7 8 9 |1 2 3 |4 5 6 
------------------- 
2 3 4 |5 6 7 |8 9 1 
5 6 7 |8 9 1 |2 3 4 
8 9 1 |2 3 4 |5 6 7 
------------------- 
3 4 5 |6 7 8 |9 1 2 
6 7 8 |9 1 2 |3 4 5 
9 1 2 |3 4 5 |6 7 8 

1 2 3 |0 5 6 |7 8 9 
4 5 6 |7 8 9 |0 2 3 
0 8 9 |1 2 3 |4 5 6 
------------------- 
2 3 0 |5 6 7 |8 9 1 
5 6 7 |8 0 1 |2 3 4 
8 9 1 |2 3 0 |5 6 7 
------------------- 
3 0 5 |6 7 8 |9 1 2 
6 7 8 |9 1 2 |3 4 0 
9 1 2 |3 4 5 |6 0 8 

Answer 2

您可以使用此代碼。我沒有製作完美數獨的矩陣，但你可以看到輸出。功能是deleteRandom（）

8 1 5 4 2 5 3 0 2 1 
3 6 0 4 5 5 3 3 5 8 
6 9 4 3 8 2 3 8 0 7 
2 9 9 1 0 5 7 6 9 2 
4 0 6 7 7 9 5 6 6 2 
2 9 1 8 8 7 9 9 8 0 
0 4 6 2 7 3 8 5 8 1 
1 8 5 2 1 8 0 4 8 7 
4 7 5 0 6 6 6 4 3 3 
9 6 3 5 6 0 4 7 1 6 

在每行和每列僅存在一個零它將改變每次程序執行時。

import java.util.ArrayList; 
import java.util.LinkedHashSet; 
import java.util.Random; 
import java.util.Set; 

public class test { 
    public static void main(String[] args) { 
     int[][] sodoku = new int[10][10]; 
     for (int i = 0; i < 10; i++) { 
      for (int j = 0; j < 10; j++) { 
       Random random = new Random(); 
       int max = 9; 
       int min = 1; 
       sodoku[i][j] = random.nextInt(max - min + 1) + min; 
      } 
     } 
     print(sodoku); 
     deleteRandom(sodoku); 
    } 

    private static void deleteRandom(int[][] sodoku) { 
     Random r = new Random(); 
     Set<Integer> rowSet = new LinkedHashSet<>(); 
     while (rowSet.size() != 10) { 
      int answer = r.nextInt(10); 
      rowSet.add(answer); 
     } 
     ArrayList<Integer> rowList = new ArrayList<>(); 
     rowList.addAll(rowSet); 

     Set<Integer> colSet = new LinkedHashSet<>(); 
     while (colSet.size() != 10) { 
      int answer = r.nextInt(10); 
      colSet.add(answer); 
     } 
     ArrayList<Integer> colList = new ArrayList<>(); 
     colList.addAll(colSet); 
     for (int i = 0; i < 10; i++) { 
      sodoku[rowList.get(i)][colList.get(i)] = 0; 
     } 
     System.out.println(); 
     print(sodoku); 
    } 

    private static void print(int[][] sodoku) { 
     for (int i = 0; i < 10; i++) { 
      for (int j = 0; j < 10; j++) { 
       System.out.print(sodoku[i][j] + " "); 
      } 
      System.out.println(); 
     } 
    } 
}