LeetCode----36. Valid Sudoku(有效数读)

Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.

The Sudoku board could be partially filled, where empty cells are filled with the character '.'.

A partially filled sudoku which is valid.

Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

//分三次判断

public class Solution {    public boolean isValidSudoku(char[][] board) {        boolean[] nine=new boolean[9];        for(int i=0;i<9;i++){            Arrays.fill(nine, false);            for(int j=0;j<9;j++){                if(!valid(nine,board[i][j])){return false;}            }        }         for(int i=0;i<9;i++){             Arrays.fill(nine, false);            for(int j=0;j<9;j++){                if(!valid(nine,board[j][i])){return false;}            }        }                for(int i=0;i<9;i+=3){            for(int j=0;j<9;j+=3){                Arrays.fill(nine, false);                for(int k=0;k<9;k++){                    if(!valid(nine,board[i+k/3][j+k%3])){return false;}                }            }        }        return true;    }        public boolean valid(boolean []arr,char target){        if(target=='.'){return true;}        int num=target-'0';        if(num<1||num>9||arr[num-1]){return false;}        arr[num-1]=true;        return true;    }}