topic link
Solution 1: Three hash tables store the number of occurrences of the corresponding position number
Hash table of row, column, box
row_haxi = [[0] * 10 for _ in range(9)] # Take num = int(board[i][j]) Let row_haxi[i][num]+=1
column_haxi = [[0] * 10 for _ in range(9)] # Take num = int(board[i][j]) so that column_haxi[j][num]+=1
box_haxi = [[0] * 10 for _ in range(9)] # Take num = int(board[i][j]) m(number of boxes): m = j//3 + i//3*3;n(number of boxes) : n = num let box_haxi[m][n]+=1
class Solution:
def isValidSudoku(self, board: List[List[str]]) -> bool:
# 行,列,box 的哈希表
row_haxi = [[0] * 10 for _ in range(9)] # 取num = int(board[i][j]) 令 row_haxi[i][num]+=1
column_haxi = [[0] * 10 for _ in range(9)] # 取num = int(board[i][j]) 令 column_haxi[j][num]+=1
box_haxi = [[0] * 10 for _ in range(9)] # 取num = int(board[i][j]) m(第几个box):m = j//3 + i//3*3;n(第几个数):n = num 令 box_haxi[m][n]+=1
for i in range(9):
for j in range(9):
if board[i][j]!='.': # 非空值时进行判断
num = int(board[i][j])
row_haxi[i][num]+=1
column_haxi[j][num]+=1
box_haxi[j//3 + i//3*3][num]+=1
# 判断是否合规
if row_haxi[i][num]>1:return False
if column_haxi[j][num]>1:return False
if box_haxi[j//3 + i//3*3][num]>1:return False
return True