循環中的新對象在 Java 中被覆蓋

Question

所以我正在嘗試創建一個新對象以添加到列表中

public void findWord(char boggle[][], boolean visited[][], int i,
                          int j, String str)
{
    visited[i][j] = true;
    str = str + boggle[i][j];

    if (hasWord(str)) {
        for (char c : str.toCharArray()) {
            Position<Character> pos = new Position<>(c, i, j);
            list.add(pos);

        }
    }

    for (int row = i - 1; row <= i + 1 && row < 4; row++)
        for (int column = j - 1; column <= j + 1 && column < 4; column++)
            if (row >= 0 && column >= 0 && !visited[row][column])
                findWord(boggle, visited, row, column, str);

    visited[i][j] = false;
}

問題是基本上每個位置（行和列）都被這個對象的最后一個實例所覆蓋，但元素本身不是。

我的職位類：

public class Position<T> {

private T element;
private int row;
private int column;

Position () {
    this(null,0,0);
}
Position (T element) {
    this.element = element;
}

Position (T element, int row, int column) {

    this.element = element;
    this.row = row;
    this.column = column;
}

public int getRow() {

    return row;
}

public int getColumn() {

    return column;
}

public T getElement() {

    return element;
}

public String toString() {

    return element + "(" + Integer.toString(row) + "," + column + ")";
}

也就是說，我打印后的 List 輸出類似於：

a(2,2) a(2,2) r(2,2) o(2,2) n(2,2)

最后一個位置在 Element 和索引中都是正確的，但所有其他位置在矩陣索引中都失敗了。 應該 ：

a(0,0) a(1,0) r(1,1) o(1,2) n(2,2)

孔類：

import java.io.*;

public class Boogle {

    LinkedList<Position<Character>> list = new LinkedList<>();

    static QuadHashTable<String> table = new QuadHashTable<>();

    String word;

    static char matrix [] [] = {

        {'a', '-', '-', '-'},
        {'a', 'r', 'o', '-'},
        {'-', '-', 'n', '-'},
        {'-', '-', '-', '-'}
    };

    public Boogle () {

        this(null);
    }

    public Boogle (char matrix [] []) {

        this.matrix = matrix;

    }

    public boolean hasWord (String s) {

        return s.equals(table.search(s));
    }

    public void findWordsUtil(char boggle[][], boolean visited[][], int i,
                              int j, String str)
    {

        visited[i][j] = true;
        str = str + boggle[i][j];

        if (hasWord(str))
            for (char c : str.toCharArray()) {
                Position<Character> pos = new Position<>(c, i, j);
                list.add(pos);
            }


        for (int row = i - 1; row <= i + 1 && row < 4; row++)
            for (int column = j - 1; column <= j + 1 && column < 4; column++)
                if (row >= 0 && col >= 0 && !visited[row][column])
                    findWordsUtil(boggle, visited, row, column, str);
        visited[i][j] = false;
    }

    public LinkedList<Position<Character>> solve () {

        String s = "";

        boolean visited[][] = new boolean[4][4];


        String str = "";


        for (int i = 0; i < 4; i++)
            for (int j = 0; j < 4; j++)
                findWordsUtil(matrix, visited, i, j, str);



        return list;
    }

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

        BufferedReader br = new BufferedReader(new FileReader("/home/dsolipa/Desktop/allWords.txt"));

        String line;

        while((line = br.readLine()) != null) {

            table.insert(line);
        }

        Boogle boogle = new Boogle(matrix);

        System.out.println(boogle.solve());

        //System.out.println(boogle.hasWord("or"));

    }
}

Answer 1

似乎只有當字符串是if (hasWord(str))傳遞if (hasWord(str))條件，並且您的 for 循環正在遍歷字符串str並在 n 的位置添加所有字符，即 (2,2)。 重新檢查 QuadHashTable 類中的實現。

請進行以下更改：

import java.io.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;

public class Boogle {

    LinkedList<Position<Character>> list = new LinkedList<>();

    LinkedList<Position<Character>> table = new LinkedList<>();
    Map indexMap = new HashMap();
    static QuadHashTable<String> table = new QuadHashTable<>();

    String word;

    static char matrix [] [] = {

        {'a', '-', '-', '-'},
        {'a', 'r', 'o', '-'},
        {'-', '-', 'n', '-'},
        {'-', '-', '-', '-'}
    };

    public Boogle () {

        this(null);
    }

    public Boogle (char matrix [] []) {

        this.matrix = matrix;

    }

    public boolean hasWord(String s) {

        return s.equals(table.search(s));

    }

    public void findWordsUtil(char boggle[][], boolean visited[][], int i,
                              int j, String str)
    {

        visited[i][j] = true;
        str = str + boggle[i][j];


        if (hasWord(str))
        {
            for (char c : str.toCharArray())
            {            
                ArrayList coordinates = (ArrayList)indexMap.get(c);
                String xy = (String)coordinates.get(0);                

                if(coordinates.size() !=1) // or check with flag in visited matrix 
                {
                    coordinates.remove(xy);
                    indexMap.put(c,coordinates);                    
                }

                String [] rowCol = xy.split(":");
                int x = Integer.parseInt(rowCol[0]);
                int y = Integer.parseInt(rowCol[1]);                        

                Position<Character> pos = new Position<>(c, x, y);
                list.add(pos);
            }
            return;


        }


        for (int row = i - 1; row <= i + 1 && row < 4; row++)
            for (int column = j - 1; column <= j + 1 && column < 4; column++)
                if (row >= 0 && column >= 0 && !visited[row][column])
                    findWordsUtil(boggle, visited, row, column, str);
        visited[i][j] = false;
    }

    public LinkedList<Position<Character>> solve () {

        String s = "";

        boolean visited[][] = new boolean[4][4];


        String str = "";

        for (int i = 0; i < 4; i++)
            for (int j = 0; j < 4; j++)
            {
                if(indexMap.get(matrix[i][j])!=null)
                {
                    ArrayList list = (ArrayList) indexMap.get(matrix[i][j]);
                    list.add(i+":"+j);
                    indexMap.put(matrix[i][j],list);
                }else if(matrix[i][j]!='-')
                {
                    ArrayList list = new ArrayList();
                    list.add(i+":"+j);
                    indexMap.put(matrix[i][j],list);
                }

            }



        for (int i = 0; i < 4; i++)
            for (int j = 0; j < 4; j++)
                findWordsUtil(matrix, visited, i, j, str);



        return list;
    }

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

        BufferedReader br = new BufferedReader(new FileReader("/home/dsolipa/Desktop/allWords.txt"));

        String line;

        while((line = br.readLine()) != null) {

            table.insert(line);
        }

        Boogle boogle = new Boogle(matrix);

        System.out.println(boogle.solve());

        //System.out.println(boogle.hasWord("or"));

    }
}