C/C++/python解題Leetcode 36 Valid Sudoku有效數獨

C/C++/python解題#Leetcode 36 Valid #Sudoku 有效數獨。數獨是經典問題。 從{1, 2, ..., 9}中，有512種不同的方式可以選擇每個數字，只能選擇一次或不選擇。 需要檢查27個條件。

 有三種條件：列、行和區塊。 每個board[i][j]正好位於一個列、一個行和一個區塊。 可以使用bitset、布林陣列或(無序)集合來記錄和檢查，並扮演Hash Tables的角色！ 

[LeetCode程式]

https://www.youtube.com/watch?v=--vVXnaKPqI&list=PLYRlUBnWnd5IdDHk2BjqXwesydU17z_xk

[code]https://leetcode.com/problems/valid-sudoku/solutions/3613853/w-explanationccpython-solution-uses-bool-arraysbitsetssets-as-hash-tables/

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Sudoku is classical problem. From {1, 2,..., 9} there are 2**9=512 different ways to choose each digit once or none. 

There are 27 conditions need to check. 

3 kinds of conditions: columns , rows and blocks. Each board[i][j] lies exactly in one column, one row and one block. bitset, boolean arrays or sets suffice to use for recording and checking and play the role of hash tables!!

 Leetcode 37. Sudoku Solver is also solved in the similar manner.