leetCode 36. Valid Sudoku(数独) 哈希

36. Valid Sudoku(合法数独)

Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.

The Sudoku board could be partially filled, where empty cells are filled with the character '.'.

A partially filled sudoku which is valid.

Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

关于数独的简介：

There are just 3 rules to Sudoku.

1.Each row must have the numbers 1-9 occuring just once.

2.Each column must have the numbers 1-9 occuring just once.

3.And the numbers 1-9 must occur just once in each of the 9 sub-boxes of the grid.

题目大意：

判断一个给定的二维数组是否是一个合法的数独矩阵。

思路:

采用set这一容器，来进行去重。

1.判断每一行是否合法。

2.判断每一列是否合法。

3.判断每一个九宫格是否合法。

代码如下：

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class  Solution { public :      bool  isValidSudoku(vector<vector< char >>& board)       {          set< char > mySet;          //1.判断每一行是否合法          for  ( int  row = 0; row < 9; row++)          {              //cout<<"检测行:"<<row<<endl;              for  ( int  column = 0; column < 9; column++)              {                  if  (board[row][column] ==  '.' )                  {                      continue ;                  }                  if  (mySet.find(board[row][column]) == mySet.end())                  {                      mySet.insert(board[row][column]);                  }                  else                  {                      return  false ;                  }              }              mySet.clear();          }                    //2.判断每一列是否合法          for  ( int  row = 0; row < 9; row++)          {              //cout<<"检测列:"<<row<<endl;              for  ( int  column = 0; column < 9; column++)              {                  if  (board[column][row] ==  '.' )                  {                      continue ;                  }                  if  (mySet.find(board[column][row]) == mySet.end())                  {                      mySet.insert(board[column][row]);                  }                  else                  {                      return  false ;                  }              }              mySet.clear();          }                //3.判断每一个九宫格是否合法          for  ( int  row = 0; row < 9; row += 3)          {              for  ( int  column = 0; column < 9; column += 3)              {                  for  ( int  i = row; i < row + 3; i++)                  {                      for  ( int  j = column; j < column + 3; j++)                      {                          if  (board[i][j] ==  '.' )                          {                              continue ;                          }                          if  (mySet.find(board[i][j]) == mySet.end())                          {                              mySet.insert(board[i][j]);                          }                          else                          {                              return  false ;                          }                      }                  }                  mySet.clear();              }          }          return  true ;      } };

本文转自313119992 51CTO博客，原文链接:http://blog.51cto.com/qiaopeng688/1837537