CodeWars: Sudoku Solution Validator Solution

Approach

Conduct 3 checks

• row check
• column check
• square check

Implementation

1function validSolution(board) {
2  const set = new Set()
3
4  // horizontal check
5  for (let row = 0; row < 9; row++) {
6    for (let col = 0; col < 9; col++) {
7      set.add(board[row][col])
8    }
9
10    if (set.size !== 9) return false
11    set.clear()
12  }
13
14  // vertical check
15  for (let col = 0; col < 9; col++) {
16    for (let row = 0; row < 9; row++) {
17      set.add(board[row][col])
18    }
19
20    if (set.size !== 9) return false
21    set.clear()
22  }
23
24  // square check
25  for (let row = 0; row < 9; row += 3) {
26    for (let col = 0; col < 9; col += 3) {
27      for (let i = 0; i < 3; i++) {
28        for (let j = 0; j < 3; j++) {
29          set.add(board[row + i][col + j])
30        }
31      }
32
33      if (set.size !== 9) return false
34      set.clear()
35    }
36  }
37
38  return true
39}

References

Original problem