package com.sogou.hadoop.test;

public class Sudoku {

/**
验证该值是否合法
*/
    public boolean isValidSudoku(char[][] board,int x,int y){
        int row,col;
        //same value in the same column
        for(row=0;row<9;row++){
            if((x!=row)&&(board[row][y]==board[x][y])){
                return false;
            }
        }
        // same value in the same row
        for(col=0;col<9;col++){
            if((y!=col)&&board[x][col]==board[x][y])
                return false;
        }
        // same value in the 3*3 block it belong to
        for(row=(x/3)*3;row<(x/3+1)*3;row++){
            for(col=(y/3)*3;col<(y/3+1)*3;col++){
                if((x!=row)&&y!=col&&board[row][col]==board[x][y])
                    return false;
            }
        }
        return true;
        
    }
//递归调用该方法，没有检测已经填写的数字而是从头开始
    public boolean solveSudoku(char[][] board){
        for(int row=0;row<9;row++){
            for(int col=0;col<9;col++){
                if(‘.‘==board[row][col]){
                    for(int i=1;i<=9;i++){
                        board[row][col]=(char) (‘0‘+i);
                        if(isValidSudoku(board, row, col)){
                            if(solveSudoku(board))
                                return true;
                        }
                        board[row][col]=‘.‘;
                    }
                    return false;
                }
            }
        }
        return true;
    }
    public static void main(String[] args) {
        
    }
}