title: LeetCode No.36
categories:
- OJ
- LeetCode
tags:
- Programing
- LeetCode
- OJ
LeetCode第三十六题
题目描述
判断一个 9x9 的数独是否有效。只需要根据以下规则,验证已经填入的数字是否有效即可。
数字 1-9 在每一行只能出现一次。
数字 1-9 在每一列只能出现一次。
数字 1-9 在每一个以粗实线分隔的 3x3 宫内只能出现一次。
上图是一个部分填充的有效的数独。
数独部分空格内已填入了数字,空白格用 ‘.’ 表示。
示例 1:
输入:
[
["5","3",".",".","7",".",".",".","."],
["6",".",".","1","9","5",".",".","."],
[".","9","8",".",".",".",".","6","."],
["8",".",".",".","6",".",".",".","3"],
["4",".",".","8",".","3",".",".","1"],
["7",".",".",".","2",".",".",".","6"],
[".","6",".",".",".",".","2","8","."],
[".",".",".","4","1","9",".",".","5"],
[".",".",".",".","8",".",".","7","9"]
]
输出: true
示例 2:
输入:
[
["8","3",".",".","7",".",".",".","."],
["6",".",".","1","9","5",".",".","."],
[".","9","8",".",".",".",".","6","."],
["8",".",".",".","6",".",".",".","3"],
["4",".",".","8",".","3",".",".","1"],
["7",".",".",".","2",".",".",".","6"],
[".","6",".",".",".",".","2","8","."],
[".",".",".","4","1","9",".",".","5"],
[".",".",".",".","8",".",".","7","9"]
]
输出: false
解释: 除了第一行的第一个数字从 5 改为 8 以外,空格内其他数字均与 示例1 相同。
但由于位于左上角的 3x3 宫内有两个 8 存在, 因此这个数独是无效的。
说明:
一个有效的数独(部分已被填充)不一定是可解的。
只需要根据以上规则,验证已经填入的数字是否有效即可。
给定数独序列只包含数字 1-9 和字符 '.' 。
给定数独永远是 9x9 形式的。
思维导图
代码
class Solution(object):
def isValidSudoku(self, board):
"""
:type board: List[List[str]]
:rtype: bool
核心思想:
实际就是一个大模拟
分别进行如下判断如果有不满足的情况则结束判断,最坏时间复杂度情况就是判断全部情况
1. 判断每行
2. 判断每列
3. 判断每个格子
针对每行每列可以采用去掉所有"."然后set判断长度是否一致
"""
nums = list(str(i) for i in range(1,10))
# dictList = dict(zip(nums,[0 for i in range(10)]))
# print(dictList)
# 判断每行
for i in range(9):
dictList = dict(zip(nums,[0 for i in range(10)]))
for j in range(9):
if board[i][j] == '.':
continue
dictList[board[i][j]] += 1
if dictList[board[i][j]] >= 2:
return False
# 判断每列
for i in range(9):
dictList = dict(zip(nums,[0 for i in range(10)]))
for j in range(9):
if board[j][i] == '.':
continue
dictList[board[j][i]] += 1
if dictList[board[j][i]] >= 2:
return False
# 判断每个格子
for i in range(9):
dictList = dict(zip(nums, [0 for i in range(10)]))
remainder = i % 3 # 余数
consult = int(i / 3) # 商
for j in range(3):
for k in range(3):
if board[j+consult*3][k+remainder*3] == '.':
continue
dictList[board[j+consult*3][k+remainder*3]] += 1
if dictList[board[j+consult*3][k+remainder*3]] >= 2:
return False
return True
if __name__ == '__main__':
s = Solution()
print(s.isValidSudoku([
["5","3",".",".","7",".",".",".","."],
["6",".",".","1","9","5",".",".","."],
[".","9","8",".",".",".",".","6","."],
["8",".",".",".","6",".",".",".","3"],
["4",".",".","8",".","3",".",".","1"],
["7",".",".",".","2",".",".",".","6"],
[".","6",".",".",".",".","2","8","."],
[".",".",".","4","1","9",".",".","5"],
[".",".",".",".","8",".",".","7","5"]
]))