Leetcode 36. Valid Sudoku (python)

题目

解法：

这道题不难，关键在于找到(i,j)位置的元素怎样同时判断row，col和box的情况。
对于row，col和box，分别对应9行，9列和9个box。用三个长度为9元素为字典的list来对应

class Solution:
    def isValidSudoku(self, board: List[List[str]]) -> bool:
        row_dic = [collections.defaultdict(int) for _ in range(9)]
        col_dic = [collections.defaultdict(int) for _ in range(9)]
        box_dic = [collections.defaultdict(int) for _ in range(9)]
        print(row_dic)
        for i in range(9):
            for j in range(9):
                num = board[i][j]
                if num != '.':
                    row_dic[i][num]+=1
                    col_dic[j][num]+=1
                    box_id = (i//3)*3 + j//3
                    box_dic[box_id][num]+=1
                    
                    if row_dic[i][num]>1 or col_dic[j][num]>1 or box_dic[box_id][num]>1:
                        return False
        
        return True