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Friday, January 11, 2013

[LeetCode] Valid Sudoku 解题报告


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.
» Solve this problem

[解题思路]
实现题。先检查行列,再检查小9格。


[Code]
1:    bool isValidSudoku(vector<vector<char> > &board) {  
2:      // Start typing your C/C++ solution below  
3:      // DO NOT write int main() function  
4:      if(board.size() == 0) return false;  
5:      int row[9], col[9];      
6:      for(int i =0; i<9; i++)  
7:      {  
8:        memset(row, 0, 9*sizeof(int));  
9:        memset(col, 0, 9*sizeof(int));  
10:        for(int j =0; j<9; j++)  
11:        {  
12:          if(board[i][j] != '.')  
13:          {   
14:            if(row[board[i][j]-49] ==1)  
15:              return false;  
16:            row[board[i][j]-49]++;  
17:          }  
18:          if(board[j][i] != '.')  
19:          {    
20:            if(col[board[j][i]-49] ==1)  
21:              return false;  
22:            col[board[j][i]-49]++;  
23:          }  
24:        }  
25:      }      
26:      for(int i =0; i< 9; i+=3)  
27:      {  
28:        for(int j =0; j<9; j+=3)  
29:        {  
30:          memset(row, 0, 9*sizeof(int));  
31:          for(int m=0; m<3; m++)  
32:          {  
33:            for(int n =0; n<3; n++)  
34:            {  
35:              if(board[m+i][n+j] == '.')  
36:                continue;  
37:              if(row[board[m+i][n+j]-49] ==1)  
38:                return false;  
39:              row[board[m+i][n+j]-49]++;  
40:            }  
41:          }  
42:        }  
43:      }  
44:      return true;  
45:    }  


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