https://leetcode.com/problems/valid-sudoku/

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
/**
 * @param {character[][]} board
 * @return {boolean}
 */
const checkArr = function(arr) {
    arr = arr.filter(v => v !== '.')
    return arr.length === [...new Set(arr)].length
}

const isValidSudoku = function(board) {
    let col = [[], [], [], [], [], [], [], [], []]
    for(let i = 0; i < 9; i++) {
        // check row
        if(!checkArr(board[i])) return false
        for(let j = 0; j < 9; j++) {
            col[j].push(board[i][j])
            // check sub box
            if (i % 3 === 0 && j % 3 === 0) {
                let box = []
                box.push(board[i][j])
                box.push(board[i][j + 1])
                box.push(board[i][j + 2])
                box.push(board[i + 1][j])
                box.push(board[i + 1][j + 1])
                box.push(board[i + 1][j + 2])
                box.push(board[i + 2][j])
                box.push(board[i + 2][j + 1])
                box.push(board[i + 2][j + 2])
                if(!checkArr(box)) return false
            }
        }
    }
    // check column
    for(let i = 0; i < col.length; i++) {
        if(!checkArr(col[i])) return false
    }
    return true
}