Algorithms—36.Valid Sudoku

public class Solution {    public boolean isValidSudoku(char[][] board) {//验证每行每列有没有重复数据for (int i = 0; i < 9; i++) {Map<Character, String> cross=new HashMap<Character, String>();Map<Character, String> vertical=new HashMap<Character, String>();for (int j = 0; j < 9; j++) {if (!(board[i][j]=='.')) {if (cross.get(board[i][j])!=null) {return false;}else {cross.put(board[i][j], "");}}if (board[j][i]!='.') {if (vertical.get(board[j][i])!=null) {return false;}else {vertical.put(board[j][i], "");}}}}//验证每个小九个字有无重复数据for (int a = 0; a < 3; a++) {for (int b = 0; b < 3; b++) {Map<Character, String> squ=new HashMap<Character, String>();for (int c = 0; c < 3; c++) {for (int d = 0; d < 3; d++) {if (board[3*a+c][3*b+d]!='.') {if (squ.get(board[3*a+c][3*b+d])!=null) {return false;}else {squ.put(board[3*a+c][3*b+d], "");}}}}}}return true;    }}