Java实现解出世界最难九宫格问题

package numberGame;

public class Point { 
    private int col;// 行号 
    private int row;// 列号 
    private boolean flag;// 真为未设置。 
    private int value; 
    // 构造点 
    public Point(int col, int row, boolean flag, int value) { 
        super(); 
        this.col = col; 
        this.row = row; 
        this.flag = flag; 
        this.value = value; 
    }

    public void changeFlag() { 
        flag = !flag; 
    }

    public boolean getFlag() { 
        return flag; 
    }

    public int getValue() { 
        return value; 
    }

    public void setValue(int value) { 
        this.value = value; 
    }

    public boolean canHere(Point[][] pArr) { 
        boolean cb = canCol(pArr); 
        boolean cr = canRow(pArr); 
        boolean cminiArr = canMiniArr(pArr); 
        return cb && cr && cminiArr; 
    } 
    //判断在小3*3格子里是否有相同元素 
    private boolean canMiniArr(Point[][] pArr) { 
        int coltemp = this.col % 3; 
        int rowtemp = this.row % 3;

        for (int i = this.col - coltemp; i < col + (3 - coltemp); i++) { 
            for (int j = this.row - rowtemp; j < row + (3 - rowtemp); j++) { 
                if(i == this.col && j == this.row){ 
                    continue; 
                }else{               
                    if(this.value == pArr[i][j].getValue()){ 
                        return false; 
                    }                
                } 
            } 
        } 
        return true; 
    }

    // 判断列上是否有相同元素 
    private boolean canRow(Point[][] pArr) { 
        for (int i = 0; i < 9; i++) { 
            if (i == this.col) { 
                continue; 
            } else { 
                if (this.value == pArr[i][this.row].value) {// 行变，列不变 
                    return false; 
                } 
            } 
        } 
        return true; 
    }

    // 判断行上是否有相同元素 
    private boolean canCol(Point[][] pArr) { 
        for (int i = 0; i < 9; i++) { 
            if (i == this.row) { 
                continue; 
            } else { 
                if (this.value == pArr[this.col][i].value) {// 列边，行不变 
                    return false; 
                } 
            } 
        } 
        return true; 
    } 
}

package numberGame;

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.ArrayList;

public class Number99 {

    public static void main(String[] args) throws IOException{ 
        Point[][] numMat = new Point[9][9]; 
        ArrayList<Point> al = new ArrayList<Point>();

        initNumMat(numMat,al);

        setNum(numMat,al); 
        printMat(numMat); 
    }

    private static void setNum(Point[][] numMat,ArrayList<Point> al) { 
        int i = 0; 
        int j = 0; 
        do{ 
            if (numMat[i][j].getFlag()) { 
                for (int v = numMat[i][j].getValue()+1; v <= 9; v++) {//给回退到的位置的值加一。 
                    numMat[i][j].setValue(v); 
                    if (numMat[i][j].canHere(numMat)) {//满足条件，不冲突。 
                        numMat[i][j].changeFlag();//改变标记为假。表示已设置过。 
                        break; 
                    }else{//满足不条件，冲突。value值自加一次 
                    }   

                    while(v == 9){//如果1-9都不能满足要求，则先将本位重置为0，并回退一格,给回退到的位置的值加一（当回退位置的值不为9时,并且保证回退到的位置不是九宫格原本的点）。 
                        numMat[i][j].setValue(0); 
                        j--; 
                        if(j==-1){ 
                            i--;j=8; 
                        } 
                        while(al.contains(numMat[i][j])){//如果回退到的位置为九宫格本来的点时，继续回退，直到不是本身的点时跳出while。 
                            j--; 
                            if(j==-1){ 
                                i--;j=8; 
                            } 
                        } 
                        numMat[i][j].changeFlag();//将标记 
                        v = numMat[i][j].getValue(); 
                    } 
                }            
            } 
            j++; 
            if(j==9){ 
                j=0;i++;//此处i++ 可能使i自加为9，故下面需要i!=9判断 
            } 
            if(i!=9){            
                while(al.contains(numMat[i][j])){ 
                    j++; 
                    if(j==9){ 
                        j=0;i++; 
                    } 
                } 
            } 
        }while(i!=9);

    }

    public static void initNumMat(Point[][] numMat,ArrayList<Point> al) throws IOException { 
        for (int i = 0; i < numMat.length; i++) { 
            for (int j = 0; j < numMat[i].length; j++) { 
                numMat[i][j] = new Point(i, j, true, 0); 
            } 
        } 
        initNumMat2(numMat, al);

    }

    public static void initNumMat2(Point[][] numMat, ArrayList<Point> al) throws IOException { 
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); 
        String[] p = new String[3]; 
        String line=null; 
        System.out.println("请按格式输入点信息（i行号, j列号 v值）,输入结束输入over: i j v ");

        while((line = br.readLine())!=null){ 
            if(line.equals("over")) 
                break; 
            p = line.trim().split(" +"); 
            numMat[Integer.parseInt(p[0])][Integer.parseInt(p[1])].setValue(Integer.parseInt(p[2])); 
            numMat[Integer.parseInt(p[0])][Integer.parseInt(p[1])].changeFlag(); 
            al.add(numMat[Integer.parseInt(p[0])][Integer.parseInt(p[1])]); 
        } 
    }

    public static void printMat(Point[][] numMat) { 
        System.out.println("--------┬---------┬---------┐");

        for (int i = 0; i < numMat.length; i++) { 
            for (int j = 0; j < numMat[i].length; j++) { 
                if ((j + 1) % 3 == 0) 
                    System.out.print(numMat[i][j].getValue() + " | "); 
                else 
                    System.out.print(numMat[i][j].getValue() + "  "); 
            } 
            if ((i + 1) % 3 == 0) 
                System.out.println("\r\n--------┼---------┼---------┤"); 
            else 
                System.out.println(); 
        } 
    }

}