1
# Runtime: 104 ms (Top 89.12%) | Memory: 14 MB (Top 35.48%)
2
class Solution:
3
    def isValidSudoku(self, board: List[List[str]]) -> bool:
4

5
        hrow = {}
6
        hcol = {}
7
        hbox = defaultdict(list)
8

9
        # CHECK FOR DUPLICATES ROWWISE
10
        for i in range(9):
11
            for j in range(9):
12

13
                # JUST THAT THE DUPLICATE SHOULDNT BE ","
14
                if board[i][j] != ".":
15

16
                    if board[i][j] not in hrow:
17
                        hrow[board[i][j]] = 1
18

19
                    else:
20
                        return False
21

22
            # CLEAR HASHMAP FOR THIS ROW
23
            hrow.clear()
24
        print("TRUE1")
25
        # CHECK FOR DUPLICATES COLUMNWISE
26

27
        for i in range(9):
28
            for j in range(9):
29

30
                # JUST THAT THE DUPLICATE SHOULDNT BE ","
31
                if board[j][i] != ".":
32

33
                    if board[j][i] not in hcol:
34
                        hcol[board[j][i]] = 1
35

36
                    else:
37
                        return False
38

39
            # CLEAR HASHMAP FOR THIS COL
40

41
            hcol.clear()
42

43
        print("TRUE2")
44

45
        # CHECK DUPLICATE IN BOX, THIS IS WHERE KEY DESIGN SKILLS COME INTO PLAY, FOR SUDOKU YOU COMBINE ROW INDICES AND COL INDICES
46

47
        for i in range(9):
48
            for j in range(9):
49

50
                i_3 = i // 3
51
                j_3 = j // 3
52

53
                # print(hbox)
54
                if board[i][j] != ".":
55

56
                    # CHECK ELEMENT OF ORIGINAL INDICE present in key i_3 , j_3
57
                    if board[i][j] not in hbox[i_3, j_3]:
58
                        # #CHECKED IN NEW KEY
59
                        hbox[i_3, j_3] = hbox[i_3, j_3] + [board[i][j]]
60

61
                    else:
62
                        return False
63

64
        return True