[Leetcode] Sudoku Solver

Write a program to solve a Sudoku puzzle by filling the empty cells.

Empty cells are indicated by the character '.'.

You may assume that there will be only one unique solution.

A sudoku puzzle...

...and its solution numbers marked in red.

Solution:

http://blog.csdn.net/zxzxy1988/article/details/8586289

public class Solution {
    public void solveSudoku(char[][] board) {
        mySudokuSolver(board);
    }

    private boolean mySudokuSolver(char[][] board) {
        // TODO Auto-generated method stub
        for(int i=0;i<board.length;++i){
            for(int j=0;j<board[0].length;++j){
                if(board[i][j]=='.'){
                    for(int k=1;k<=9;++k){
                        board[i][j]=(char) (k+'0');
                        if(isValid(board,i,j)&&mySudokuSolver(board)){
                            return true;
                        }
                        board[i][j]='.';　　//这里这个细节不要忘掉！！，你把后边儿的“.“改成数字后，发现做不下去了，得回溯，那你
　　　　　　　　　　　　　　　　　　　　　　　　　　　//得把这个数字改回"."啊

                    }
                    return false;
                }
            }
        }
        return true;
    }

    private boolean isValid(char[][] board, int row, int col) {
        // TODO Auto-generated method stub
        for(int i=0;i<board.length;++i){
            if(i!=row&&board[i][col]==board[row][col])
                return false;
        }
        for(int i=0;i<board[0].length;++i){
            if(i!=col&&board[row][i]==board[row][col])
                return false;
        }
        for(int i=(row/3)*3;i<(row/3+1)*3;++i){
            for(int j=(col/3)*3;j<(col/3+1)*3;++j){
                if(i!=row&&j!=col&&board[i][j]==board[row][col])
                    return false;
            }
        }
        return true;
    }
}