389. Valid Sudoku【LintCode java】

Description

Determine whether a Sudoku is valid.

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

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

Clarification

What is Sudoku?

• http://sudoku.com.au/TheRules.aspx
• https://zh.wikipedia.org/wiki/數獨
• https://en.wikipedia.org/wiki/Sudoku
• http://baike.baidu.com/subview/961/10842669.htm

Example

The following partially filed sudoku is valid.

解题：判断数独是否有效。如果每一行、每一列、每一个小方块里的数不重复，就算有效。当然，前提必须是1~9之间。此题空白部分是用“ . ”表示的，要注意一下。具体做法为，检查行、列、方块，把这些数拿出来，放在一个一维数组中，判断这个一维数组里的数，满不满足相应的条件。代码如下：

public class Solution {
    /**
     * @param board: the board
     * @return: whether the Sudoku is valid
     */
    public boolean isValidSudoku(char[][] board) {
        // write your code here
        char[]temp = new char[9];
        for(int i = 0; i < 9; i++){
            //检查行
            for(int j = 0; j < 9; j++){
                temp[j] = board[i][j];
            }
            if(judge(temp) == false){
                return false;
            }
            //检查列
            for(int j = 0; j < 9; j++){
                temp[j] = board[j][i];
            }
            if(judge(temp) == false){
                return false;
            }
        }
        //小格子
        for(int i = 0; i < 3; i++){
            for(int j = 0; j < 3; j++){
                int b = 0;
                for(int k = 0 + i * 3; k < 3 + i * 3; k++){
                    for(int m = 0 + j * 3; m < 3 + j * 3; m++){
                        temp[b++] = board[k][m];
                    }
                }
                if(judge(temp) == false)
                return false;

            }
        }
        return true;
    }
    public boolean judge(char[]temp){
        for(int i =0; i < 9; i++){
            if(temp[i] > '9' || temp[i] < '1' ){
                if(temp[i] != '.')
                   return false;
            }
        }
        for(int i = 1; i < 9; i++){
            for(int j = 0; j < i; j++){
                if(temp[i] == temp[j] ){
                    if(temp[i] != '.')
                        return false;
                }
            }
        }
        return true;
    }
}