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.

主要歷程
1 理解題目，這道題不是填數獨，而是valid數獨而且如果有看Note，會發現

Only the filled cells need to be validated.

這局決定了 ‘.’是不校驗的，是返回true的。

2 九宮數獨的規則一共有3個，行檢驗，和列檢驗比較簡單。主要是用js去做 除法得到的浮點數用於陣列比較坑爹。必須向下取整Math.floor()才能用於索引。。

3還有array 並沒有clear方法也要注意！

4 九宮的數是 1-9的，所以轉成索引是減去 ‘1’的！

/**
 * @param {character[][]} board
 * @return
 
 {boolean}
 */

var checkedArray = new Array(9)
var isValidSudoku = function(board) {

    for (var i = 0 ; i < board.length ; i++)
    {
       checkedArray.fill(0)
        for(var j = 0 ; j < board.length ; j ++)
        {
            if (checkValue(board[i][j]) === false )
            {

                return
 
 false
            }
        }

    }



    for ( i = 0 ; i < board.length ; i++)
    {
         checkedArray.fill(0)
        for( j = 0 ; j < board.length ; j++)
        {
            if (checkValue(board[j][i]) === false )
            {

                return false
            }
        }
    }

     checkedArray.fill(0)

    for ( i = 0 ; i < board.length ; i+=3)
    {

        for( j = 0 ; j < board.length ; j+=3)
        {
             checkedArray.fill(0)

            for (var k = 0 ; k < 9; k++)
            { 
               // console.log("checking "+i+ k/3+" , "+j + k%3)
                if (checkValue(board[i+   Math.floor(k/3)][j + k%3]) === false )
                {

                  return false
                }

            }
        }
    }

   return true;

};

var checkValue = function(value)
{
      //  console.log("checking value "+value)

    if(value == '.') //根據題意不校驗
    {   
        return  true;
    }

    var index = value - '1';
    if (index < 0 || index > 9 ||  checkedArray[index] > 0)
    {
     //   console.log("value is "+index +"/" +checkedArray[index])
        return false;
    }
    else
    {
   //  console.log("push index is "+index)
        checkedArray[index] = 1;
    }

    return true;
}