Sudoku Solver

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.

Java代码：

public class Solution {boolean[][] row = new boolean[9][9];boolean[][] col = new boolean[9][9];boolean[][] blo = new boolean[9][9];public void solveSudoku(char[][] board) {    for(int i=0;i<9;i++)        for(int j =0;j<9;j++){            int temp =board[i][j]-'1';            if(board[i][j]!='.'){                row[i][temp]=true;                col[j][temp]=true;                blo[3*(i/3)+j/3][temp]=true;            }        }    solveHelper(0,0,board);}public boolean solveHelper(int i, int j, char[][] board){    if(i==9)        return true;    if(board[i][j]!='.'){        if(j<8)            return solveHelper(i,j+1,board);        else             return solveHelper(i+1,0,board);    }else for(int k =0;k<9;k++){            if(row[i][k]==false&&col[j][k]==false&&blo[3*(i/3)+j/3][k]==false){                board[i][j] = (char)(k+'0'+1);                row[i][k]=true;                col[j][k]=true;                blo[3*(i/3)+j/3][k]=true;                if(j<8&&solveHelper(i,j+1,board))                    return true;                else if(j==8&&solveHelper(i+1,0,board))                    return true;                else{                    board[i][j] = '.';                    row[i][k]=false;                    col[j][k]=false;                    blo[3*(i/3)+j/3][k]=false;                }            }        }    return false;}}