package com.sudoku; public class sodu { private int[][] sodu = null; private int[] tai = null; /** * 构造方法 因为每执行一次递归都会把数组tai元素全置为-1. 所以在执行一次递归后需要重新给tai赋值。 */ public sodu() { do { this.init(); tai = getMixArray(); generateNum(0, 0, 0, 0); // upleft tai = getMixArray(); generateNum(0, 3, 0, 3); // up tai = getMixArray(); generateNum(0, 6, 0, 6); // upright tai = getMixArray(); generateNum(3, 0, 3, 0); // left tai = getMixArray(); generateNum(3, 6, 3, 6); // right tai = getMixArray(); generateNum(6, 0, 6, 0); // downleft tai = getMixArray(); generateNum(6, 3, 6, 3); // down tai = getMixArray(); generateNum(6, 6, 6, 6); // downright } while (this.checkZERO()); } /** * 得到一个随机数组(元素1到9无重复) * * @param array */ private int[] getMixArray() { int[] array = { 1, 2, 3, 4, 5, 6, 7, 8, 9 }; for (int i = 0; i < array.length; i++) { int rand = (int) (Math.random() * 9); int middle = array[i]; array[i] = array[rand]; array[rand] = middle; } return array; } /** * 初始化数独数组 会初始化正中间的3*3矩阵 */ private void init() { sodu = new int[9][9]; int[] array = this.getMixArray(); for (int i = 0; i < 3; i++) { for (int j = 0; j < 3; j++) { sodu[3 + i][3 + j] = array[i * 3 + j]; } } } /** * 打印 */ public void print() { String flag = "~"; for (int i = 0; i < 9; i++) { for (int j = 0; j < 9; j++) { System.out.print("[" + sodu[i][j] + "]"); if (j % 3 == 2 && j < 8) { System.out.print(flag); } } System.out.println(); if (i % 3 == 2 && i < 8) { for (int k = 0; k < 14; k++) { System.out.print(" "); System.out.print(flag); } System.out.println(); } } } /** * 递归方法 * * 生成(row,erect)处的值 * * xi和xj 分别是初始调用该方法时的row和erect * * @return */ private boolean generateNum(int row, int erect, int xi, int xj) { if (row - xi == 3) return true; for (int i = 0; i < tai.length; i++) { if (tai[i] != -1 && isGood(row, erect, tai[i])) { sodu[row][erect] = tai[i]; tai[i] = -1; if (erect - xj < 2) { if (generateNum(row, erect + 1, xi, xj)) { return true; } else { tai[i] = sodu[row][erect]; sodu[row][erect] = 0; continue; } } else { if (generateNum(row + 1, xj, xi, xj)) { return true; } else { tai[i] = sodu[row][erect]; sodu[row][erect] = 0; continue; } } } } return false; } /** * 判断数字number是否可以用在坐标(x,y)处 */ private boolean isGood(int i, int j, int number) { for (int m = 0; m < 9; m++) { if (sodu[i][m] == number) { return false; } } for (int n = 0; n < 9; n++) { if (sodu[n][j] == number) { return false; } } return true; } /** * 判断数独数组中是否有0 */ private boolean checkZERO() { for (int i = 0; i < 9; i++) { for (int j = 0; j < 9; j++) { if (sodu[i][j] == 0) { return true; } } } return false; } /** * 程序入口 * * @param args */ public static void main(String[] args) { new sodu().print(); } }