A valid Sudoku is a 9×9 grid puzzle where each row, column, and 3×3 subgrid contains the numbers 1 to 9 exactly once. Here is an example of a valid Sudoku:
5 3 4 | 6 7 8 | 9 1 2
6 7 2 | 1 9 5 | 3 4 8
1 9 8 | 3 4 2 | 5 6 7
---------------------
8 5 9 | 7 6 1 | 4 2 3
4 2 6 | 8 5 3 | 7 9 1
7 1 3 | 9 2 4 | 8 5 6
---------------------
9 6 1 | 5 3 7 | 2 8 4
2 8 7 | 4 1 9 | 6 3 5
3 4 5 | 2 8 6 | 1 7 9/**
* @param {character[][]} board
* @return {boolean}
*/
var isValidSudoku = function(board) {
if (!board) {
return false;
}
const rowArr = [...Array(9)].map(x => new Object());
const colArr = [...Array(9)].map(x => new Object());
const boxObj = {};
for (let i = 0; i < 9; i++) {
let boxRow = 3 * Math.floor(i / 3) + '.';
for (let j = 0; j < 9; j++) {
let c = board[i][j];
if (c !== '.') {
if (c in rowArr[i]) {
return false;
} else {
rowArr[i][c] = true;
}
if (c in colArr[j]) {
return false;
} else {
colArr[j][c] = true;
}
const boxKey = boxRow + (3 * Math.floor(j / 3));
if (!(boxKey in boxObj)) {
boxObj[boxKey] = {};
}
if (c in boxObj[boxKey]) {
return false;
} else {
boxObj[boxKey][c] = true;
}
}
}
}
return true;
}
/**
* @param {character[][]} board
* @return {boolean}
*/
// var isValidSudoku = function(board) {
// if (!board) {
// return false;
// }
// for (let i = 0; i < board.length; i++) {
// for (let j = 0; j < board[0].length; j++) {
// const c = board[i][j];
// if ( c!== '.' && !valid(c, i , j, board)) {
// return false;
// }
// }
// }
// return true;
// };
// var valid = function(c, i, j, board) {
// const rowStart = 3 * Math.floor(i / 3);
// const colStart = 3 * Math.floor(j / 3);
// for (let k = 0; k < 9; k++) {
// if ((k !== j && board[i][k] === c) || (k !== i && board[k][j] === c)) {
// return false;
// }
// let row = rowStart + Math.floor(k / 3);
// let col = colStart + (k % 3);
// if (!(row === i && col === j) && c === board[row][col]) {
// return false;
// }
// }
// return true;
// }