验证战舰板，二维数组，如何检查板有效性的可能性？

Question

在给定一个包含 1 和 0 的二维数组时，在 Java 中编写代码以验证战舰板，其中 1 是船的一部分，0 是大海。以下是需要了解的规则：

-必须有单艘战列舰（4 格尺寸）、2 艘巡洋舰（3 号尺寸）、3 艘驱逐舰（2 号尺寸）和 4 艘潜艇（1 号尺寸）。不允许任何额外的船只，以及丢失的船只。

-每艘船都必须是一条直线，除了潜艇，它们只是单格。

-船不能重叠，但可以与任何其他船接触。

我的方法只是计算 2 号 3 号 4 号船的所有可能连接，并确保它们大于所需尺寸船的数量，这并不适用于所有情况，我也是将有助于检查是否恰好有 20 个放置 1 的问题是，如果我们有 0 1 1 1 1 0 0 0 0 0 它会告诉我它是有效的，尽管它肯定不是（因为它是一排和一艘船）并且当我有以下内容时：应该是 false 但我的 returns true->

  {0,0,0,0,0,0,0,1,1,0},
 {0,0,0,0,0,0,0,1,1,1},
 {0,0,0,0,0,0,1,1,1,0},
 {0,1,0,0,0,0,0,0,0,0},
 {0,1,0,0,1,1,1,0,0,0},
 {0,0,0,0,1,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,1,0,0,0,0,1,1,0},
 {0,0,1,0,0,0,0,1,1,0},

或这应该是错误的，但我的 returns true->

 {0,1,1,1,0,0,0,0,0,0},
 {0,0,0,1,1,1,0,0,0,0},
 {0,1,1,1,0,0,0,0,0,0},
 {0,0,0,1,1,1,0,0,0,0},
 {0,1,1,1,0,1,1,0,0,0},
 {0,1,0,0,0,0,1,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},

这里是一个例子，代码在它应该return正确的时候工作：

 {1,0,0,0,0,1,1,0,0,0},
 {1,1,0,0,0,0,0,0,1,0},
 {1,1,0,0,1,1,1,0,1,0},
 {1,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,1,1,1,0,0,0},
 {0,0,0,1,0,0,0,0,1,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},

但是当我有这个例子时：

{0,0,1,0,0,0,0,1,1,0},
 {0,1,1,0,0,0,0,0,0,0},
 {1,1,1,1,1,0,0,0,0,1},
 {0,0,1,1,1,1,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,1,1,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,1,0,0,1},
 {0,0,0,0,0,0,0,0,0,1},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},

应该是错误的，但我的代码 return 是正确的。那么我怎样才能找到一种方法来重组我的代码或找到一个解决方案，当我得到一个板时我真的不知道它是否有效。但是我的 Java 程序可以吗？

这是我为此尝试的代码，我的方法是制作一个列表，其中包含检查特定船只从最大到较小的所有变化（最大的是 [4 3 3 2 2 2] 不包括1's 因为它会显着增加变化量，我可以用不同的方式更有效地检查它，最小的变化是 [2 2 2 3 3 4] 4 最后，它们重复的原因是因为 2 有 x3 艘船所以 2 2 2，x2 尺寸 3 船所以 3 3 和 x1 尺寸 4 船所以只有一个）这是代码：

import java.util.*;

class Permute{
    public static List<int[]> l;
    Permute(){
        this.l=new ArrayList<int[]>();
    }
    static void permute(java.util.List<Integer> arr, int k){
        for(int i = k; i < arr.size(); i++){
            java.util.Collections.swap(arr, i, k);
            permute(arr, k+1);
            java.util.Collections.swap(arr, k, i);
        }
        if (k == arr.size() -1){
            l.add(arr.stream()
            .map(i -> (i == null ? 0 : i))
            .mapToInt(Integer::intValue)
            .toArray()); 
        }
    }
     public static List<int[]> get(){
        Permute.permute(java.util.Arrays.asList(2,2,2,3,3,4), 0);Collections.reverse(l);
        return l;
    }
}

public class BF {
    private static int[][] fields,copy;
    private static int[] ship= {0,0,3,2,1};
    public BF(int[][] field) {
        fields=field;
//        print(field);
        this.copy=field;
    }
    
    public boolean validate() {
        int cnt=counter(fields);
        if(cnt!=20)return false;
        Permute p= new Permute();//permutation constructor
        List<int[]> list=p.get();//gets our specific permution
        for (int i = 0; i < list.size(); i++) {//run through each option of our permution list
            copy=fields;
            ship=new int[]{0,0,3,2,1};//amount of ships needed
            boolean flag=check(fields,list.get(i));//checks if the permution variation is true or false
            int cnt1=counter(copy);//we checked boats of size 2 3 4 but not 1 which means if its valid then there should be 4 boats left
            if(flag && cnt1==4)return true;
        }
        return false;
    }
   public static boolean check(int[][] field,int[] ships){
           for(int i=0;i<ships.length;i++) {//go through the array and loop through the variation
                int num=getBoat(fields, ships[i]);//if the boat is true on the certain boat we are checking
                ship[num]--;//then -1 and at the end we want it to be [<=0,0,0,0,0]
           }
           int counter=0;
           for(int i=2;i<ship.length;i++) {
               if(ship[i]==0)counter++;//if [0,0,0]
           }
           if(counter==3) {return true;}//then return true
         return false;
    }

  public static int getBoat(int[][] field,int num) {
      int dire=0,r=0,c=0;String dir="row";
     for (int col = 0; col < fields[0].length; col++) {
        for (int row = 0; row < fields.length; row++) {//loop through each coordinate
            if (copy[row][col] == 1) {//check if its part of a boat at the coor
              int length=field.length;dir="row";dire=row;
               for(int j=0;j<2;j++) {//go horizontal then vertical
                   if(j==1) {length=field[0].length;dir="col";dire=col;}//change length to vertical
                    if(dire+num-1<length) {//make sure we don't get outofbounds error
                        int cnt=0;
                        for(int i=0;i<num;i++) {//checks each coor according to type of boat we are checking
                            if(dir.equals("row")) {r=row+i;c=col;}
                            else if(dir.equals("col")){r=row;c=col+i;}
                            if(copy[r][c]==1) {//check
                                cnt++;//copy of battle field becomes 0
                            }
                            else copy=fields;//otherwise break this loop since it is not relevant anymore on this coor
                            if(cnt==num) {
                                for(int k=0;k<num;k++) {
                                    if(dir.equals("row")) {r=row+k;c=col;}
                                    else if(dir.equals("col")){r=row;c=col+k;}
                                    copy[r][c]=0;//now we know its valid length and make it 0 on the copy
                                    }
                                    return cnt;
                        }}}} //if num is correct then return it
                }
        }
     }return 0;
     }
  public static int counter(int[][] f) {// counts amount of tiles on the board with 1's
      int cnt=0;
    for (int col = 0; col < f[0].length; col++) {
        for (int row = 0; row < f.length; row++) {
            if (f[row][col] == 1) {
             cnt++; 
            }
            }
    }
    return cnt;
  }
    public static void print(int[][] field) {//prints the board
        for (int row = 0; row < field.length; row++) {
            for (int col = 0; col < field[0].length; col++) {
                if(col<field[0].length-1 && col!=0) {
                    System.out.print( field[row][col]+",");
                }
                else if(col==field[0].length-1){
                    System.out.print( field[row][col]+"},");
                }
                else if(col==0) {
                    System.out.print(" {"+ field[row][col]+",");
                }
            }
            System.out.println("");
            }
  System.out.println("\n");
    }

}

代码现在似乎运行很好，但当它假设时 return 不正确。

这里有一些代码应该 return 正确但 return 错误的示例：

{1,0,0,0,0,1,1,0,0,0},
 {1,0,1,0,0,0,0,0,1,0},
 {1,0,1,0,1,1,1,0,1,0},
 {1,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,1,1,1,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,1,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},

此处为真：

 {1,0,0,0,0,0,0,0,1,0},
 {0,0,1,0,0,1,1,1,1,0},
 {0,0,1,1,0,0,0,0,0,0},
 {0,0,1,1,1,1,1,0,0,0},
 {0,0,1,1,1,0,0,0,0,0},
 {0,0,1,0,1,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},

此处为真：

 {1,0,0,0,0,1,1,0,0,0},
 {1,1,0,0,0,0,0,0,1,0},
 {1,1,0,0,1,1,1,0,1,0},
 {1,0,0,0,0,0,0,0,0,0},
 {1,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,1,1,1,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},

此处为真：

 {1,1,1,0,0,0,0,0,0,0},
 {1,1,0,0,0,0,0,0,1,0},
 {1,1,0,0,1,1,1,0,1,0},
 {1,0,0,0,0,0,0,0,0,0},
 {1,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,1,1,1,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},

此处为真：

{1,0,0,0,0,1,1,0,0,0},
 {1,1,0,0,0,0,0,0,1,0},
 {1,1,0,0,1,1,1,0,1,0},
 {1,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,1,1,1,0,0,0},
 {0,0,0,1,0,0,0,0,1,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},

但这些示例中的代码 return 是错误的

所以在这个例子中

 {1,1,1,0,0,0,0,0,0,0},
 {1,1,0,0,0,0,0,0,1,0},
 {1,1,0,0,1,1,1,0,1,0},
 {1,0,0,0,0,0,0,0,0,0},
 {1,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,1,1,1,0,0,0},
 {0,0,0,0,0,0,0,0,1,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},

有效，因为：

[![在此处输入图片描述][1]][1]

但是我的代码采用了大小的第一个选项，这就是我的代码 returns 为 false-

时发生的情况

[![在此处输入图片描述][2]][2]

那么我需要添加什么来解决这个问题？

public class BF {
    private static int[][] fields;
    public BF(int[][] field) {
        fields=field;
        print(field);
        
    }
    public boolean validate() {
        int cnt=counter(fields);
        if(cnt!=20)return false;
        return checkBoard(fields, new int[]{4,3,3,2,2,2},0,new int[] {3,2,1});
    }


    public static boolean checkBoard(int[][] board,int[] SizePlacement,int k,int[] shipAmount){
       if (counter(board)==4 ) {
            return true;
        }
       int cnt=0;//SizePlacement={4,3,3,2,2,2}, ship(changes)={3,2,1}, k(starts at 0) is placement in ships[]
       for (int row = 0; row < board.length; row++) {
           for (int col = 0; col < board[0].length; col++) {
             if(board[row][col]==1 && row+SizePlacement[k]<board.length) {//vertically
               cnt=1;
               for(int i=1;i<SizePlacement[k];i++) {//check vertically
                   if(board[row+i][col]==1) {cnt++;}
                   }
               if(cnt>=SizePlacement[k]) {
                   int[][] newBoard = deepcopy(board);
                   newBoard= remove(newBoard , row, col, SizePlacement[k], "ver");
                   shipAmount[SizePlacement[k]-2]--;
                   if(shipAmount==new int[]{0,0,0}) {return true;}
                   if(k+1<SizePlacement.length && checkBoard(newBoard,SizePlacement,k+1,shipAmount)) {return true;}
                  shipAmount[SizePlacement[k]-2]++;   
               }
           }
            if(board[row][col]==1 && col+SizePlacement[k]<board[0].length) {//horizontally
               cnt=1;
               for(int i=1;i<SizePlacement[k];i++) {//check horizontally
                   if(board[row][col+i]==1) {cnt++;}
                   }
               if(cnt>=SizePlacement[k]) {
                  int[][] newBoard = deepcopy(board);
                  newBoard= remove(newBoard , row, col, SizePlacement[k], "hor");
                   shipAmount[SizePlacement[k]-2]--;
                   if(shipAmount==new int[]{0,0,0}) {return true;}
                   if(k+1<SizePlacement.length &&checkBoard(newBoard,SizePlacement,k+1,shipAmount)) {
                     return true;
                   }
                  shipAmount[SizePlacement[k]-2]++;
                   }
               }
           }
       }
       return false;
    }
   public static int[][] remove(int[][] newBoard,int row,int col,int size,String orien){
       int[][] removedBoard= deepcopy(newBoard);
       if(orien=="ver") {
           for(int i=0;i<size;i++) {
               removedBoard[row+i][col]=0;
           }
           print(removedBoard);
           return removedBoard;
       }
       else if(orien=="hor") {
           for(int i=0;i<size;i++) {
               removedBoard[row][col+i]=0;
           }
           print(removedBoard);
           return removedBoard;
       }
       return removedBoard;
   }
   public static int[][] deepcopy(int[][] fields){
    int[][] copy= new int[fields.length][fields[0].length];
    for (int row = 0; row < fields.length; row++) {
        for (int col = 0; col < fields[0].length; col++) {
                   copy[row][col]= fields[row][col];
               }
            }
    return copy;
   }
   public static int counter(int[][] f) {// counts amount of tiles on the board with 1's
          int cnt=0;
        for (int col = 0; col < f[0].length; col++) {
            for (int row = 0; row < f.length; row++) {
                if (f[row][col] == 1) {
                 cnt++; 
                }
                }
        }
        return cnt;
      }
        public static void print(int[][] field) {//prints the board
            for (int row = 0; row < field.length; row++) {
                for (int col = 0; col < field[0].length; col++) {
                    if(col<field[0].length-1 && col!=0) {
                        System.out.print( field[row][col]+",");
                    }
                    else if(col==field[0].length-1){
                        System.out.print( field[row][col]+"},");
                    }
                    else if(col==0) {
                        System.out.print(" {"+ field[row][col]+",");
                    }
                }
                System.out.println("");
                }
      System.out.println("\n");
        }
}

这似乎有一些错误（与解决方案不同），不确定对此的帮助将不胜感激 [1]: https://i.stack.imgur.com/bX32n.png [2]: https://i.stack.imgur.com/tFP1N.png

Answer 1

如果所有船只的位置都有效，则该板有效。

这意味着您需要一个船舶数据结构。首先，一个简单的数据结构可能是 [ ship_type, [ position_1 , position_2, position_3 ] ]

一旦你有了船的数据结构，检查所有的船都在板上，没有两艘船共享一个位置，以及板上每种类型的船的正确数量是微不足道的.每种类型的正确数量的船只可以进入 Fleet 数据结构。

对于一艘船，您会很快意识到，可以用字母来渲染了解其舰队的一方的棋盘。但另一块板是“特殊的”，因为没有船舶能见度。这意味着（在真实游戏中）Battleship 由两种板组成，即命中检测板和船舶定位板。它们看起来相似只是制造的副作用。

现在 HitBoard AI 将如何尝试追捕一艘船？好吧，他们会从随机放置或模式开始。两种方法各有优势。一旦检测到命中，它将参考场上剩余船只的数量，并开始沿水平和垂直轴探测以找到船只的完整位置。一旦它被告知“You sunk my”，它就会知道沉船必须从游戏中移除。

 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,1,1,1,1,0,0},
 {0,0,0,0,1,1,1,1,0,0},
 {0,0,0,0,1,1,1,1,0,0},
 {0,0,0,0,1,1,1,1,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},

由两艘战列舰、一艘驱逐舰、一艘潜艇和一艘巡洋舰组成。如果没有额外的信息，就不可能知道大多数船只是从左到右还是从上到下。

有时甚至无法在进行游戏时知道船的位置。有趣的是，这些信息可能并不总是足以了解船只的位置。这有时会发生在船只处于紧密排列的编队中，并且您通过在已经记录命中的一排或一列（或两列）方格内进行攻击来击沉船只。在这种情况下，您的点击可能不会定义沉没项目的结束。

如果目标是在没有位置以外的任何额外信息的情况下验证棋盘，那么您需要采用不同的方法。

按大小排序船只。
在当前的棋盘位置，重复直到没有可用的船。
Select最大的船。
搜索最大船只的所有可能位置，生成没有船只位置标记的新板。
如果无法放置飞船，则板不是有效的板配置。
如果船舶列表为空且板上有标记，则该板不是有效的板配置。
如果船舶列表为空且棋盘为空，则标记处于有效的棋盘配置中。
重复，针对步骤 2 中生成的板独立处理所有板。

这是一种蛮力方法；但是，在蛮力方法中有许多可能的优化。

Answer 2

我认为解决这个问题的最佳方法是从最大的开始迭代放置船只。算法的大致轮廓是这样的：

Select未放置的最大船
考虑所有可能展示位置的列表
对于每个可能的放置，从数组中删除那些 1，然后重复该过程，不包括您刚刚放置的飞船

由于您没有对某些点的船舶类型进行编码，您可以从已放置的船舶上移除点，然后继续尝试放置船舶。这将随着船只数量的增加而爆炸，但我认为它对于这个小解决方案来说已经足够快了。

Answer 3

尝试不允许联系的解决方案：

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;

public class BattleFieldValidator {
  private static final int SIZE = 10;

  private static class Ship {
    public int     col;
    public int     row;
    public boolean horizontal;
    public int     size;

    @Override
    public String toString() {
      return "size " + size + " at (" + (row + 1) + "," + (col + 1) + ") " + (horizontal ? "horizontal" : "vertical");
    }
  }

  public static void validateField(int[][] field) {
    // 10x10 field
    if(field.length != SIZE || field[0].length != SIZE) {
      throw new RuntimeException("invalid field dimensions");
    }

    // each cell 0 or 1
    for(int row = 0; row < SIZE; row++) {
      for(int col = 0; col < SIZE; col++) {
        int cellValue = field[row][col];
        if(cellValue != 0 && cellValue != 1) {
          throw new RuntimeException("invalid cell value at (" + (row + 1) + "," + (col + 1) + ")");
        }
      }
    }

    print(field);

    boolean[][] discoveredShipCells = new boolean[SIZE][SIZE];
    List<Ship> ships = new ArrayList<>();

    for(int row = 0; row < SIZE; row++) {
      for(int col = 0; col < SIZE; col++) {
        if(discoveredShipCells[row][col]) {
          continue;
        }

        if(field[row][col] == 1) {
          Ship ship = discoverShip(field, discoveredShipCells, row, col);
          ships.add(ship);
        }
      }
    }

    Collections.sort(ships, (a, b) -> b.size - a.size);
    System.out.println("discovered ships:");
    ships.forEach(s -> System.out.println(s));

    if(ships.stream().filter(s -> s.size == 4).count() != 1) {
      throw new RuntimeException("battleship(size 4) count != 1");
    }

    if(ships.stream().filter(s -> s.size == 3).count() != 2) {
      throw new RuntimeException("cruiser(size 3) count != 2");
    }

    if(ships.stream().filter(s -> s.size == 2).count() != 3) {
      throw new RuntimeException("destroyer(size 2) count != 3");
    }

    if(ships.stream().filter(s -> s.size == 1).count() != 4) {
      throw new RuntimeException("submarine (size 1) count != 4");
    }

    // ok
  }

  private static Ship discoverShip(int[][] field, boolean[][] discoveredShipCells, int shipStartRow, int shipStartCol) {
    Ship ship = new Ship();
    ship.row = shipStartRow;
    ship.col = shipStartCol;

    int horizontalSize = 0;
    for(int col = ship.col; col < SIZE && field[ship.row][col] == 1; col++) {
      horizontalSize++;
      discoveredShipCells[ship.row][col] = true;
    }

    int verticalSize = 0;
    for(int row = ship.row; row < SIZE && field[row][ship.col] == 1; row++) {
      verticalSize++;
      discoveredShipCells[row][ship.col] = true;
    }

    if(horizontalSize > 1 && verticalSize > 1) {
      throw new RuntimeException("ship extending both horizontally and vertically at (" + (ship.row + 1) + "," + (ship.col + 1) + ")");
    }

    ship.horizontal = verticalSize == 1;
    ship.size = ship.horizontal ? horizontalSize : verticalSize;

    // validate ship surrounded by ocean cells
    if(ship.horizontal) {
      // left & right
      validateOceanCell(ship, field, ship.row, ship.col - 1);
      validateOceanCell(ship, field, ship.row, ship.col + ship.size);
      // top & bottom
      for(int col = ship.col - 1; col <= ship.col + ship.size; col++) {
        validateOceanCell(ship, field, ship.row - 1, col);
        validateOceanCell(ship, field, ship.row - 1, col);
      }
    }
    else {
      // top & bottom
      validateOceanCell(ship, field, ship.row - 1, ship.col);
      validateOceanCell(ship, field, ship.row + ship.size, ship.col);
      // left & right
      for(int row = ship.row - 1; row <= ship.row + ship.size; row++) {
        validateOceanCell(ship, field, row, ship.col - 1);
        validateOceanCell(ship, field, row, ship.col + 1);
      }
    }

    return ship;
  }

  private static void validateOceanCell(Ship ship, int[][] field, int row, int col) {
    if(row < 0 || row >= SIZE || col < 0 || col >= SIZE) {
      return /* outside field, ignore */;
    }

    if(field[row][col] == 1) {
      throw new RuntimeException("ship " + ship + " not surrounded by whater at (" + (row + 1) + "," + (col + 1) + ")");
    }
  }

  private static void print(int[][] field) {
    System.out.println();
    for(int row = 0; row < SIZE; row++) {
      System.out.println(Arrays.stream(field[row]).boxed().collect(Collectors.toList()));
    }
  }
}

和最少的测试：

public class BattleFieldTest {

  @org.junit.Test
  public void test1() {
    int[][] battleField = { //
        { 1, 0, 0, 0, 0, 1, 1, 0, 0, 0 }, //
        { 1, 0, 1, 0, 0, 0, 0, 0, 1, 0 }, //
        { 1, 0, 1, 0, 1, 1, 1, 0, 1, 0 }, //
        { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, //
        { 0, 0, 0, 0, 0, 0, 0, 0, 1, 0 }, //
        { 0, 0, 0, 0, 1, 1, 1, 0, 0, 0 }, //
        { 0, 0, 0, 0, 0, 0, 0, 0, 1, 0 }, //
        { 0, 0, 0, 1, 0, 0, 0, 0, 0, 0 }, //
        { 0, 0, 0, 0, 0, 0, 0, 1, 0, 0 }, //
        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } };
    BattleFieldValidator.validateField(battleField);
  }

  @org.junit.Test
  public void test2() {
    int[][] battleField = { //
        { 0, 0, 0, 1, 0, 1, 0, 1, 0, 0 }, //
        { 0, 0, 0, 0, 0, 1, 0, 1, 0, 0 }, //
        { 0, 0, 1, 0, 0, 1, 0, 1, 0, 0 }, //
        { 0, 0, 0, 0, 0, 0, 0, 1, 0, 0 }, //
        { 1, 1, 0, 0, 1, 0, 0, 0, 0, 0 }, //
        { 0, 0, 0, 0, 0, 0, 0, 1, 1, 0 }, //
        { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0 }, //
        { 0, 0, 0, 0, 0, 1, 0, 0, 1, 0 }, //
        { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0 }, //
        { 0, 1, 1, 0, 0, 0, 0, 0, 0, 0 }, };
    BattleFieldValidator.validateField(battleField);
  }
}

示例输出：

[1, 0, 0, 0, 0, 1, 1, 0, 0, 0]
[1, 0, 1, 0, 0, 0, 0, 0, 1, 0]
[1, 0, 1, 0, 1, 1, 1, 0, 1, 0]
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[0, 0, 0, 0, 0, 0, 0, 0, 1, 0]
[0, 0, 0, 0, 1, 1, 1, 0, 0, 0]
[0, 0, 0, 0, 0, 0, 0, 0, 1, 0]
[0, 0, 0, 1, 0, 0, 0, 0, 0, 0]
[0, 0, 0, 0, 0, 0, 0, 1, 0, 0]
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
discovered ships:
size 4 at (1,1) vertical
size 3 at (3,5) horizontal
size 3 at (6,5) horizontal
size 2 at (1,6) horizontal
size 2 at (2,3) vertical
size 2 at (2,9) vertical
size 1 at (5,9) horizontal
size 1 at (7,9) horizontal
size 1 at (8,4) horizontal
size 1 at (9,8) horizontal

Answer 4

我认为@AlexRudenko 意味着这会更容易验证：

 {0,0,0,0,0,0,0,2,2,0},
 {0,0,0,0,0,0,0,3,3,3},
 {0,0,0,0,0,4,4,4,4,0},
 {0,2,0,0,0,0,0,0,1,0},
 {0,2,0,0,3,3,3,0,0,0},
 {0,0,0,0,1,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,0,0,0,0,0,0,0,0},
 {0,0,2,0,0,0,0,2,1,0},
 {0,0,2,0,0,0,0,2,1,0},

Answer 5

由于我们无法确定地区分飞船，因此我们需要尝试不同的可能性。尝试将一艘船放在一个可能的位置（保留该位置），然后递归地尝试下一艘船。（这可能也是其他人的建议）。对于有这么几艘船的 10x10 板，计算非常快。

这是我尝试实现它的尝试。

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicInteger;

public class Main {
    private static final int SIZE = 10;
    private static final int HORIZONTAL = 0;
    private static final int VERTICAL = 1;

    private static final int[] shipSizes = {4, 3, 3, 2, 2, 2};
    private static final int NR_OF_ONES = 4;

    private static final int[][] board1 = {
            {1, 0, 0, 0, 0, 1, 1, 0, 0, 0},
            {1, 1, 0, 0, 0, 0, 0, 0, 1, 0},
            {1, 1, 0, 0, 1, 1, 1, 0, 1, 0},
            {1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 1, 0},
            {0, 0, 0, 0, 1, 1, 1, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 1, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 1, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};

    private static AtomicInteger counter = new AtomicInteger();

    public static void main(String[] args) {
        int[][] board = board1;

        validateBoard(board);
        long start = System.nanoTime();
        boolean valid = checkBoard(board, 0);
        long time = System.nanoTime() - start;
        System.out.println("Board is " + (valid ? "" : "NOT ") + "valid");
        System.out.println("Checked board in " + time + " ns");
    }

    private static boolean checkBoard(int[][] currentBoard, int shipSizePos) {
        if (shipSizePos >= shipSizes.length) {
            return true;
//            return countOnes(currentBoard) == NR_OF_ONES;
        }
        List<Ship> currentSizeShips = findPossibleShips(currentBoard, shipSizes[shipSizePos]);
        boolean valid = false;
        for (Ship ship : currentSizeShips) {
            if(checkBoard(removeShipFromBoard(currentBoard, ship), shipSizePos + 1)) {
                return true;
            }
        }
        return valid;
    }

    private static int[][] removeShipFromBoard(int[][] board, Ship ship) {
        int[][] newBoard = new int[SIZE][SIZE];
        for (int r = 0; r < SIZE; ++r) {
            for (int c = 0; c < SIZE; ++c) {
                if ((ship.orientation == HORIZONTAL && r == ship.row && (c >= ship.col && c < ship.col + ship.size))
                        || (ship.orientation == VERTICAL && c == ship.col && (r >= ship.row && r < ship.row + ship.size))) {
                    newBoard[r][c] = 0;
                } else {
                    newBoard[r][c] = board[r][c];
                }
            }
        }
        return newBoard;
    }

    private static List<Ship> findPossibleShips(int[][] board, int size) {
        List<Ship> ships = new ArrayList<>();
        for (int r = 0; r < SIZE; ++r) {
            for (int c = 0; c < SIZE; ++c) {
                if (board[r][c] == 1) {
                    if (isPossibleHorizontalShip(board, size, r, c)) {
                        ships.add(new Ship(r, c, size, HORIZONTAL));
                    }
                    if (isPossibleVerticalShip(board, size, r, c)) {
                        ships.add(new Ship(r, c, size, VERTICAL));
                    }
                }
            }
        }
        return ships;
    }

    private static boolean isPossibleHorizontalShip(int[][] board, int size, int row, int col) {
        if (SIZE - col < size) {
            return false;
        }
        int c;
        for (c = col; c < SIZE && board[row][c] == 1; ++c) ;
        return c - col >= size;
    }

    private static boolean isPossibleVerticalShip(int[][] board, int size, int row, int col) {
        if (SIZE - row < size) {
            return false;
        }
        int r;
        for (r = row; r < SIZE && board[r][col] == 1; ++r) ;
        return r - row >= size;
    }

    private static int countOnes(int[][] board) {
        int ones = 0;
        for (int r = 0; r < SIZE; ++r) {
            for (int c = 0; c < SIZE; ++c) {
                ones += board[r][c];
            }
        }
        return ones;
    }

    private static void validateBoard(int[][] board) {
        for (int r = 0; r < SIZE; ++r) {
            for (int c = 0; c < SIZE; ++c) {
                if (!(board[r][c] == 0 || board[r][c] == 1)) {
                    throw new IllegalArgumentException("Illegal character at " + r + ", " + c);
                }
            }
        }
        if (countOnes(board) != Arrays.stream(shipSizes).sum() + NR_OF_ONES) {
            throw new IllegalArgumentException("Wrong number of ship pieces");
        }
    }

    private static class Ship {
        private final int row;
        private final int col;
        private final int size;
        private final int orientation;

        public Ship(int row, int col, int size, int orientation) {
            this.row = row;
            this.col = col;
            this.size = size;
            this.orientation = orientation;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            Ship ship = (Ship) o;
            return row == ship.row && col == ship.col && size == ship.size && orientation == ship.orientation;
        }

        @Override
        public int hashCode() {
            return Objects.hash(row, col, size, orientation);
        }

        @Override
        public String toString() {
            return "Ship{" +
                    "row=" + row +
                    ", col=" + col +
                    ", size=" + size +
                    ", orientation=" + orientation +
                    '}';
        }
    }
}

首先验证板以确保它只包含 0 和 1 以及正确数量的 1
从最大到最小浏览非 1 号船只的列表。
搜索当前尺码的可能展示位置，删除一个并检查下一个尺码的分支
当只剩下1s时，板就OK了（我们依靠验证的计数是正确的）

验证战舰板，二维数组，如何检查板有效性的可能性？

Validating a Battleship board, 2d array, how to check possibilities for boards validity?

java

puzzle