写一个程序，解决数独求解的问题
空的格子用字符 '.'代替。
你可以假设只有一个解
一个数独 ...
...红色的数字就是解.
下面是我的代码
package com.zhazhapan.algorithm.backtracking;
public class SudokuSolve {
public static void main(String[] args) {
// TODO Auto-generated method stub
String[] string = { "..9748...", "7........", ".2.1.9...", "..7...24.", ".64.1.59.", ".98...3..", "...8.3.2.",
"........6", "...2759.." };
char[][] board = new char[9][9];
// 初始化数独
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
board[i][j] = string[i].charAt(j);
}
}
new SudokuSolve().solveSudoku(board);
}
public void solveSudoku(char[][] board) {
if (board == null || board.length != 9 || board[0].length != 9) {
return;
}
if (solve(board, 0, 0)) {
// 打印结果
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
System.out.print(board[i][j] + " ");
}
System.out.println();
}
}
}
public boolean solve(char[][] board, int i, int j) {
if (j == 9) {
if (i == 8)
return true;
i++;
j = 0;
}
if (board[i][j] != '.') {
return solve(board, i, j + 1);
}
for (char k = '1'; k <= '9'; k++) {
if (isValid(board, i, j, k)) {
board[i][j] = k;
if (solve(board, i, j + 1))
return true;
else
board[i][j] = '.';
}
}
return false;
}
public boolean isValid(char[][] board, int i, int j, char c) {
for (int k = 0; k < 9; k++) {
if (board[i][k] != '.' && board[i][k] == c)
return false;
if (board[k][j] != '.' && board[k][j] == c)
return false;
if (board[i / 3 * 3 + k / 3][j / 3 * 3 + k % 3] != '.'
&& board[i / 3 * 3 + k / 3][j / 3 * 3 + k % 3] == c)
return false;
}
return true;
}
}
