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SudokuSolver.java
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SudokuSolver.java
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package com.leetcode.submissions;
/**
* Create by ranzd on 2018/1/31
*
* @author cm.zdran@foxmail.com
*/
public class SudokuSolver {
public static boolean filling(char[][] board, int[][] row, int[][] col, int[][] square) {
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
if (board[i][j] == '.') {
for (int k = 0; k < 9; k++) {
int sIndex = i / 3 * 3 + j / 3;
if (row[i][k] == 0 && col[j][k] == 0 && square[sIndex][k] == 0) {
board[i][j] = ((k + 1) + "").charAt(0);
row[i][k] = col[j][k] = square[sIndex][k] = 1;
if (filling(board, row, col, square)) {
return true;
} else {
board[i][j] = '.';
row[i][k] = col[j][k] = square[sIndex][k] = 0;
}
}
}
return false;
}
}
}
return true;
}
public static void solveSudoku(char[][] board) {
int[][] row = new int[9][9];
int[][] col = new int[9][9];
int[][] square = new int[9][9];
//init array
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
if (board[i][j] != '.') {
int num = board[i][j] - '0' - 1;
//根据 i、j 计算属于第几个九宫格
int sIndex = i / 3 * 3 + j / 3;
row[i][num] = col[j][num] = square[sIndex][num] = 1;
}
}
}
filling(board, row, col, square);
}
public static void main(String[] args) {
char[][] board = new char[][]{
new char[]{'.', '.', '9', '7', '4', '8', '.', '.', '.'},
new char[]{'7', '.', '.', '.', '.', '.', '.', '.', '.'},
new char[]{'.', '2', '.', '1', '.', '9', '.', '.', '.'},
new char[]{'.', '.', '7', '.', '.', '.', '2', '4', '.'},
new char[]{'.', '6', '4', '.', '1', '.', '5', '9', '.'},
new char[]{'.', '9', '8', '.', '.', '.', '3', '.', '.'},
new char[]{'.', '.', '.', '8', '.', '3', '.', '2', '.'},
new char[]{'.', '.', '.', '.', '.', '.', '.', '.', '6'},
new char[]{'.', '.', '.', '2', '7', '5', '9', '.', '.'}
};
solveSudoku(board);
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
System.out.printf(board[i][j] + ",");
}
System.out.println();
}
}
}